Cancer vaccine composition

ABSTRACT

A cancer vaccine composition for human leukocyte antigen (HLA)-A*0206-positive persons, comprising a protein product of the tumor suppressor gene WT1 or a partial peptide thereof.

This application is a Continuation of U.S. application Ser. No. 12/746,257, filed on Jun. 4, 2010, which is a National Stage of PCT/JP2008/072160, filed on Dec. 5, 2008.

TECHNICAL FIELD

The present invention relates to a cancer vaccine composition for human leukocyte antigen (HLA)-A*0206-positive persons, comprising a protein product of the tumor suppressor gene Wilms' tumor 1 (WT1) (hereinafter sometimes abbreviated as WT1 protein) or a partial peptide thereof (hereinafter sometimes abbreviated as WT1 peptide). The present invention also relates to a cancer vaccine composition for HLA-A*0206-positive persons, comprising DNA or RNA encoding the above-mentioned WT1 protein or WT1 peptide, a method for inducing WT1-specific CTLs, a method for inducing dendritic cells that present a cancer antigen, and a method of cancer diagnosis for HLA-A*0206-positive persons, and a method of cancer treatment or prevention in HLA-A*0206-positive persons.

The present invention further relates to a cancer vaccine composition for HLA-A*0201-positive persons, comprising a modified peptide of the WT1 peptide.

BACKGROUND ART

The Wilms' tumor gene WT1 was isolated as a gene associated with tumorigenesis in Wilms' tumor, which is a pediatric renal tumor (see nonpatent literature 1). This gene encodes a zinc finger transcription factor associated with the regulatory mechanism of cell growth and differentiation, and apoptosis and tissue development.

The WT1 gene was originally classified as a tumor suppressor gene. However, based on the recent evidences shown in the following (i) to (iii):

-   (i) high expression of the wild-type WT1 gene in various human     malignant tumors and solid cancers including hematopoietic malignant     tumors such as leukemia and myelodysplastic syndromes (MDS), -   (ii) growth inhibition of human leukemia cells and solid cancer     cells treated by WT1 antisense oligonucleotides, and -   (iii) growth promotion and differentiation inhibition of mouse     myeloid precursor cells by constitutive expression of the wild-type     WT1 gene,     it is suggested that the wild-type WT1 gene exhibits an oncogenic     effect rather than a tumor suppressive effect on various malignant     diseases (see patent literature 1).

There is also known high expression of the WT1 gene in solid cancers, such as gastric cancer, colon cancer, lung cancer, breast cancer, germ cell cancer, hepatic cancer, skin cancer, bladder cancer, prostate cancer, uterine cancer, cervical cancer and ovarian cancer (see patent literature 2).

In general, the immune system for eliminating foreign substances comprises humoral immunity, in which macrophages, which recognize an antigen and serve as antigen presenting cells, helper T cells, which recognize the antigen presented by the macrophages and produce various lymphokines to activate other T cells, and B lymphocytes, which differentiate into antibody producing cells via the actions of the lymphokines, are involved; and cell-mediated immunity, in which cytotoxic T lymphocytes (CTLs), which are produced through differentiation in response to antigen presentation, attack and destroy target cells.

Currently, it has been considered that cancer immunity is mainly based on cell-mediated immunity in which CTLs are involved. In the CTL-based cancer immunity, precursor T cells recognize a cancer antigen presented in the form of a complex of a major histocompatibility complex (MHC) class I and the cancer antigen, and thereby differentiate and grow into CTLs, which attack and destroy cancer cells. In this case, the cancer cell presents, on the cell surface, a complex of the MHC class I antigen and the cancer antigen, which is the target of the CTLs (see nonpatent literatures 2 to 5). MHC is called as a human leukocyte antigen (HLA) in humans.

It is considered that the above-mentioned cancer antigen, which is presented by an MHC class I antigen on the surfaces of cancer cells, i.e., target cells, is a peptide of about 8 to 12 amino acids produced through intracellular protease-mediated processing of an antigen protein synthesized in cancer cells (see nonpatent literatures 2 to 5). Currently, search for antigen proteins of various cancers is underway, but only a few proteins have been identified as a cancer specific antigen.

The present inventor synthesized polypeptides that each consist of 7 to 30 contiguous amino acids based on the amino acid sequence of the WT1 gene expression product and each contain at least one amino acid presumably serving as an anchor amino acid for binding with HLA-A*2402 or HLA-A*0201, confirmed that these peptides bind with HLA-A*2402 or HLA-A*0201 (these peptides are HLA-A*2402- or HLA-A*0201-restricted), and found that the binding of the peptides with HLA-A*2402 or HLA-A*0201 induces CTLs, resulting in cytotoxic response to target cells (hereinafter abbreviated as CTL response). From this fact, these peptides were identified as a CTL epitope derived from the WT1 gene expression product (WT protein).

At this point, WT1-specific CTL epitopes only for HLA-A*2402 and HLA-A*0201 (see patent literature 3), HLA-A*3303 (see patent literature 4) or HLA-A*1101 are identified (see patent literature 5). It is confirmed that CTL responses induced by the polypeptides disclosed by the above literatures are restricted by HLA-A*2402, HLA-A*0201, HLA-A*3303 and HLA-A*1101.

This indicates a possibility that the protein product of the tumor suppressor gene WT1 is a promising tumor rejection antigen, also called as a tumor associated antigen (TAA). In fact, high levels of WT1-specific CTLs or high-titer anti-WT1 antibodies were observed not in peripheral blood of healthy blood donors, but in that of cancer patients.

However, HLA types are diverse enough to serve as markers for identifying individuals. In the HLAs, MHC class I antigens are classified into HLA-A, HLA-B and HLA-C, and MHC class II antigens are classified into HLA-DP, HLA-DQ and HLA-DR. Each class has several types of antigens. The antigen binding site of each HLA has genetic polymorphism. For example, it is known that HLA-A, HLA-B and HLA-C have 27 or more, 59 or more, and 10 or more kinds of polymorphisms (alleles), respectively.

Therefore, there has been a desire to identify a cancer antigen that binds to other types of HLAs than HLA-A*2402, HLA-A*0201, HLA-A*3303 and HLA-A*1101 and induces a CTL response, and to thereby apply immunotherapy to a wider range of subjects.

Meanwhile, the following three of modified WT1 peptides were reported in two documents:

the WT1₁₈₇P1Y peptide (YLGEQQYSV; SEQ ID NO: 12), the WT1₁₂₆P1Y peptide (YMFPNAPYL; SEQ ID NO: 35) (see patent literature 6 for the above two peptides), and the WT1₁₂₆P9M peptide (RMFPNAPYM; SEQ ID NO: 52) (see patent literature 7).

Further, the following two peptides were reported in the written argument for the examination of European patent No. 1127068:

the WT1₁₂₆P2L peptide (RLFPNAPYL; SEQ ID NO: 39) and the WT1₁₂₆P2L&P9V peptide (RLFPNAPYV; SEQ ID NO: 75) (see nonpatent literature 7).

However, it has never been reported whether these WT1 modified peptides serve as a cancer antigen that binds to other types of HLAs than HLA-A*2402, HLA-A*0201, HLA-A*3303 and HLA-A*1101 and induces a CTL response.

-   Patent Literature 1: JP-A 9-104629 -   Patent Literature 2: JP-A 11-035484 -   Patent Literature 3: WO 00/06602 pamphlet -   Patent Literature 4: Japanese Patent Application No. 2006-045287 -   Patent Literature 5: Japanese Patent Application No. 2006-355356 -   Patent Literature 6: WO 2005/053618 pamphlet -   Patent Literature 7: WO 2007/016466 pamphlet -   Non Patent Literature 1: Gessler, M. et al., Nature, vol. 343, pp.     774-778, 1990 -   Non Patent Literature 2: Cur. Opin. Immunol., vol. 5, p. 709, 1993 -   Non Patent Literature 3: Cur. Opin. Immunol., vol. 5, p. 719, 1993 -   Non Patent Literature 4: Cell, vol. 82, p. 13, 1995 -   Non Patent Literature 5: Immunol. Rev., vol. 146, p. 167, 1995 -   Non Patent Literature 6: Mol. Cell. Biol., vol. 11, p. 1707, 1991 -   Non Patent Literature 7: The written argument for the examination of     European patent No. 1127068

SUMMARY OF INVENTION Problem to be Solved by the Invention

An object of the present invention is to apply, further to HLA-A*0206-positive persons, a method of cancer treatment and/or prevention for patients with malignant tumors including leukemia, the method being based on a protein product of the tumor suppressor gene WT1 (WT1 protein) or a partial peptide thereof (WT1 peptide).

Means for Solving the Problem

The present inventor conducted intensive studies to achieve the above-mentioned object. As a result, he found that the WT1₁₈₇ peptide (SLGEQQYSV (SEQ ID NO: 2)) and the WT1₁₂₆ peptide (RMFPNAPYL (SEQ ID NO: 3)) each derived from the human WT1 protein, which were known to induce HLA-A*0201-restricted CTLs only, surprisingly induce HLA-A*0206-restricted CTLs as well. Under the circumstances where only the peptides described in WO 00/06602 pamphlet were known as a WT1 peptide that induces HLA-A*0201-restricted CTLs, the present inventor found that a modified peptide of the WT1₁₈₇ peptide (also referred to as a modified WT1₁₈₇ peptide) and a modified peptide of the WT1₁₂₆ peptide (also referred to as a WT1₁₂₆ modified peptide) also bind to an HLA-A*0201 molecule. Based on these findings, the present inventor conducted further intensive studies and completed the present invention.

Namely, the present invention relates to the following (1) to (17).

-   (1) A cancer vaccine composition for human leukocyte antigen     (HLA)-A*0206-positive persons, comprising a protein product of the     tumor suppressor gene WT1 or a partial peptide thereof. -   (2) The composition according to the above (1), wherein the protein     product of the tumor suppressor gene WT1 is the protein of the     following (a) or (b): -   (a) a protein consisting of the amino acid sequence of SEQ ID NO: 1,     or -   (b) a protein consisting of an amino acid sequence comprising     deletion, substitution or addition of one to several amino acids in     the amino acid sequence (a), either of which is immunogenic in     HLA-A*0206-positive persons. -   (3) The composition according to the above (1), wherein the partial     peptide is -   the WT1₁₈₇ peptide: Ser Leu Gly Glu Gln Gln Tyr Ser Val (SEQ ID NO:     2), -   the WT1₁₂₆ peptide: Arg Met Phe Pro Asn Ala Pro Tyr Leu (SEQ ID NO:     3), -   the WT1₁₈₇P1F peptide: Phe Leu Gly Glu Gin Gln Tyr Ser Val (SEQ ID     NO: 11), -   the WT1₁₈₇P2M peptide: Ser Met Gly Glu Gln Gln Tyr Ser Val (SEQ ID     NO: 16), -   the WT1₁₈₇P3M peptide: Ser Leu Met Glu Gln Gln Tyr Ser Val (SEQ ID     NO: 20), -   the WT1₁₂₆P1F peptide: Phe Met Phe Pro Asn Ala Pro Tyr Leu (SEQ ID     NO: 34), -   the WT1₁₂₆P2L peptide: Arg Leu Phe Pro Asn Ala Pro Tyr Leu (SEQ ID     NO: 39), -   the WT1₁₂₆P3M peptide: Arg Met Met Pro Asn Ala Pro Tyr Leu (SEQ ID     NO: 46) or -   the WT1₁₂₆P9V peptide: Arg Met Phe Pro Asn Ala Pro Tyr Val (SEQ ID     NO: 49). -   (4) The composition according to the above (1) to (3), further     comprising an adjuvant. -   (5) A cancer vaccine composition for HLA-A*0206-positive persons,     comprising DNA encoding a protein product of the tumor suppressor     gene WT1 or a partial peptide thereof. -   (6) A cancer vaccine composition for HLA-A*0206-positive persons,     comprising RNA encoding a protein product of the tumor suppressor     gene WT1 or a partial peptide thereof. -   (7) A method for inducing WT1-specific CTLs, comprising culturing,     in the presence of a protein product of the tumor suppressor gene     WT1 or a partial peptide thereof, peripheral blood mononuclear cells     (PBMCs) derived from an HLA-A*0206-positive person, to obtain     WT1-specific CTLs induced therefrom. -   (8) A method for inducing dendritic cells that present a protein     product of the tumor suppressor gene WT1 or a partial peptide     thereof, comprising culturing, in the presence of the protein     product or a partial peptide thereof, immature dendritic cells     derived from an HLA-A*0206-positive person, to obtain dendritic     cells induced therefrom which present the protein product or a     partial peptide thereof. -   (9) A method of cancer diagnosis for HLA-A*0206-positive persons,     comprising -   i) a step of detecting or quantifying a protein product of the tumor     suppressor gene WT1 or a partial peptide thereof, an antibody     thereagainst or WT1-specific CTLs in a sample from an     HLA-A*0206-positive person, and a step of comparing the amount of     the protein or a partial peptide thereof, an antibody thereagainst     or the WT1-specific CTLs, with that in the case where cancer is not     developed, or -   ii) a step of administering an HLA-A*0206-positive subject     WT1-specific CTLs induced by the method mentioned in the above (7)     or dendritic cells induced by the method mentioned in the above (8),     and a step of determining the position or region of the CTLs or     dendritic cells in the HLA-A*0206-positive subject. -   (10) A cancer vaccine composition for HLA-A*0201-positive persons,     comprising the following peptide: -   a modified peptide of the WT1₁₈₇ peptide: Ser Leu Gly Glu Gln Gln     Tyr Ser Val (SEQ ID NO: 2) or the WT1₁₂₆ peptide: Arg Met Phe Pro     Asn Ala Pro Tyr Leu (SEQ ID NO: 3), either of which is a partial     peptide of a protein product of the tumor suppressor gene WT1, the     modified peptide being immunogenic in HLA-A*0201-positive persons. -   (11) The composition according to the above (10), wherein the     modified peptide is -   the WT1₁₈₇P1F peptide: Phe Leu Gly Glu Gln Gln Tyr Ser Val (SEQ ID     NO: 11), -   the WT1₁₈₇P2M peptide: Ser Met Gly Glu Gln Gln Tyr Ser Val (SEQ ID     NO: 16), -   the WT1₁₈₇P3M peptide: Ser Leu Met Glu Gln Gln Tyr Ser Val (SEQ ID     NO: 20), -   the WT1₁₂₆P1F peptide: Phe Met Phe Pro Asn Ala Pro Tyr Leu (SEQ ID     NO: 34), -   the WT1₁₂₆P2L peptide: Arg Leu Phe Pro Asn Ala Pro Tyr Leu (SEQ ID     NO: 39), -   the WT1₁₂₆P3M peptide: Arg Met Met Pro Asn Ala Pro Tyr Leu (SEQ ID     NO: 46) or -   the WT1₁₂₆P9V peptide: Arg Met Phe Pro Asn Ala Pro Tyr Val (SEQ ID     NO: 49). -   (12) A method of cancer treatment or prevention, comprising     administering an HLA-A*0206-positive person a composition containing     a protein product of the tumor suppressor gene WT1 or a partial     peptide thereof. -   (13) A protein product of the tumor suppressor gene WT1 or a partial     peptide thereof for cancer treatment or prevention in     HLA-A*0206-positive persons. -   (14) A method of cancer treatment or prevention, comprising     administering an HLA-A*0201-positive person a composition containing     the following peptide: -   a modified peptide of the WT1₁₈₇ peptide: Ser Leu Gly Glu Gln Gln     Tyr Ser Val (SEQ ID NO: 2) or the WT1₁₂₆ peptide: Arg Met Phe Pro     Asn Ala Pro Tyr Leu (SEQ ID NO: 3), either of which is a partial     peptide of a protein product of the tumor suppressor gene WT1, the     modified peptide being immunogenic in HLA-A*0201-positive persons. -   (15) The following peptide: -   a modified peptide of the WT1₁₈₇ peptide: Ser Leu Gly Glu Gln Gln     Tyr Ser Val (SEQ ID NO: 2) or the WT1₁₂₆ peptide: Arg Met Phe Pro     Asn Ala Pro Tyr Leu (SEQ ID NO: 3), either of which is a partial     peptide of a protein product of the tumor suppressor gene WT1, the     modified peptide being immunogenic in HLA-A*0201-positive persons, -   for cancer treatment or prevention in HLA-A*0201-positive persons. -   (16) A method of cancer treatment or prevention, comprising     introducing RNA encoding a protein product of the tumor suppressor     gene WT1 or a partial peptide thereof into dendritic cells of an     HLA-A*0206-positive person. -   (17) RNA encoding a protein product of the tumor suppressor gene WT1     or a partial peptide thereof for cancer treatment or prevention in     HLA-A*0206-positive persons.

The present invention also relates to use of a protein product of the tumor suppressor gene WT1 or a partial peptide thereof for production of a cancer vaccine composition used for cancer treatment or prevention in HLA-A*0206-positive persons.

The present invention also relates to use of the following peptide:

-   a modified peptide of the WT1₁₈₇ peptide: Ser Leu Gly Glu Gln Gln     Tyr Ser Val (SEQ ID NO: 2) or the WT1₁₂₆ peptide: Arg Met Phe Pro     Asn Ala Pro Tyr Leu (SEQ ID NO: 3), either of which is a partial     peptide of a protein product of the tumor suppressor gene WT1, the     modified peptide being immunogenic in HLA-A*0201-positive persons, -   for production of a cancer vaccine composition used for cancer     treatment or prevention in HLA-A*0201-positive persons.

The “cancer vaccine composition” as used herein refers to a medicament used for cancer prevention or treatment via inoculation or administration to an animal including a human. The “treatment” refers to, besides completely curing disease state, stopping progression of disease state by inhibiting progression and/or aggravation of symptoms to some degree even falling short of a complete cure; or improving all or a part of disease state in a direction towards a cure. The “prevention” refers to preventing, inhibiting or delaying disease development.

The following terms: peripheral blood mononuclear cells, immature dendritic cells, WT1-specific CTLs, samples etc. derived from HLA-A*0206-positive or HLA-A*0201-positive persons refer to peripheral blood mononuclear cells, immature dendritic cells, WT1-specific CTLs, biological specimens etc., such as blood, which are isolated or collected from HLA-A*0206-positive or HLA-A*0201-positive persons, respectively. The WT1-specific CTLs derived from HLA-A*0206-positive or HLA-A*0201-positive persons also include CTLs induced from peripheral blood mononuclear cells, immature dendritic cells or biological specimens such as blood, which are isolated or collected from HLA-A*0206-positive or HLA-A*0201-positive persons.

Effect of the Invention

The present invention enables in vivo and in vitro induction of WT1-specific CTLs in HLA-A*0206-positive subjects. Although the subjects of immunotherapy using a vaccine comprising the WT1 protein or WT1 peptide have conventionally been limited to HLA-A*0201-positive patients and HLA-A*2402-positive patients, the present invention can widen the range of the subjects to HLA-A*0206-positive patients. HLA-A2, which is a serotype of HLA class I antigens, is the most frequent in Caucasians (about 50%), and the large majority have HLA-A*0201, while about 4% of Caucasians have HLA-A*0206. On the other hand, HLA-A24 is the most frequent serotype in Japanese people (about 58%), and the large majority have HLA-A*2402. About 42% of Japanese people have HLA-A2. Among them, only about 43% have HLA-A*0201, and the others have HLA-A*0206 or HLA-A*0207. In other words, about 18% of Japanese people have HLA-A*0201, and about 17% of Japanese people have HLA-A*0206. Therefore, the fact that at least an HLA-A*0206-restricted CTL epitope was identified from Japanese people as well as an HLA-A*0201-restricted CTL epitope is significantly useful to widen the subjects of cancer immunotherapy to HLA-A*0206-positive persons. Since 14% of Chinese people and 9% of South Korean people have this allele, it is possible to apply the cancer vaccine composition of the present invention to a further wider range of subjects.

The cancer vaccine composition of the present invention is useful for treatment of WT1-expressing cancers such as hematopoietic tumors and solid cancers in HLA-A*0206-positive persons. The cancer vaccine composition of the present invention is also useful for prevention of cancer development in HLA-A*0206-positive persons.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows the cytotoxic activity of WT1₁₈₇ peptide-specific CTLs induced from PBMCs of an HLA-A*0206-positive healthy blood donor. FIG. 1 a shows the cytotoxic activity against ⁵¹Cr-labeled B-LCLs. FIG. 1 b shows that the cytotoxic activity against ⁵¹Cr-labeled autologous B-LCLs increases in parallel with the concentration of the WT1₁₈₇ peptide used to pulse the PBMCs with.

FIG. 2 shows the cytotoxic activity of WT1₁₈₇ peptide-specific CTLs induced from PBMCs of an HLA-A*0206-positive healthy blood donor. FIGS. 2 a and 2 b show the respective cytotoxic activities, against ⁵¹Cr-labeled B-LCLs, of CTLs separately obtained from two healthy blood donors other than the blood donor of FIG. 1 a.

FIG. 3 a shows the cytotoxic activity of WT1₁₈₇ peptide-specific CTLs against B-LCLs transformed with the WT1 gene, or B-LCLs transformed with a mock vector. FIG. 3 b shows the cytotoxic activity of WT1₁₈₇ peptide-specific CTLs against 0206K562 cells, K562 cells, KH88 cells or JY cells.

FIG. 4 shows the inhibition of the cytotoxic activity of WT1₁₈₇ peptide-specific CTLs by HLA class I and/or class II antibodies.

FIG. 5 shows the cytotoxic activity, against ⁵¹Cr-labeled B-LCLs, of WT1₁₂₆ peptide-specific CTLs induced from PBMCs of an HLA-A*0206-positive healthy blood donor.

FIGS. 6 a and 6 b show the respective cytotoxic activities of WT1₁₂₆ peptide-specific CTLs separately induced from two different donors, against 0206K562 cells, K562 cells, KH88 cells or JY cells.

FIG. 7 shows the results of the flow cytometric analysis of CTLs stained with the HLA tetramer bound to the WT1₁₂₆ peptide and the anti-CD8 antibody. The CTLs have been induced by stimulation of PBMCs from the HLA-A*0201-positive donor 1 with modified peptides.

FIG. 8 shows the measurement results of the cytotoxic activity of CTLs induced by stimulation of PBMCs from the HLA-A*0201-positive donor 1 with the WT1₁₂₆P1F peptide.

FIG. 9 shows the measurement results of the cytotoxic activity of CTLs induced by stimulation of PBMCs from the HLA-A*0201-positive donor 1 with the WT1₁₂₆P2L peptide.

FIG. 10 shows the results of the flow cytometric analysis of CTLs stained with the HLA tetramer bound to the WT1₁₂₆ peptide and the anti-CD8 antibody. The CTLs have been induced by stimulation of PBMCs from the HLA-A*0201-positive donor 2 with the WT1₁₂₆P2L peptide.

FIG. 11 shows the measurement results of the cytotoxic activity of CTLs induced by stimulation of PBMCs from the donor 2 with the WT1₁₂₆P2L peptide.

FIG. 12 shows the measurement results of the cytotoxic activity of CTLs induced by stimulation of PBMCs from the HLA-A*0206-positive donor 3 with modified WT1₁₂₆ peptides.

FIG. 13 shows the measurement results of the cytotoxic activity of CTLs induced by stimulation of PBMCs from the HLA-A*0206-positive donor 3 with the WT1₁₂₆P9V peptide.

FIG. 14 shows the measurement results of the cytotoxic activity of CTLs induced by stimulation of PBMCs from the HLA-A*0206-positive donor 4 with modified WT1₁₂₆ peptides.

FIG. 15 shows the measurement results of the cytotoxic activity of CTLs induced by stimulation of PBMCs from the HLA-A*0206-positive donor 4 with modified WT1₁₂₆ peptides.

FIG. 16 shows the measurement results of the cytotoxic activity of CTLs induced by stimulation of PBMCs from an HLA-A*0201-positive donor with modified WT1₁₈₇ peptides.

FIG. 17 shows the measurement results of the cytotoxic activity of CTLs induced by stimulation of PBMCs from an HLA-A*0206-positive donor with the WT1₁₈₇P1F peptide.

FIG. 18 shows the measurement results of the cytotoxic activity of CTLs induced by stimulation of PBMCs from an HLA-A*0206-positive donor with the WT1₁₈₇P2M peptide.

FIG. 19 shows the evaluation results of modified WT1₁₈₇ peptides on the activity of inducing specific cell-mediated immunity.

FIG. 20 shows the evaluation results of modified WT1₁₈₇ peptides on the activity of inducing specific cell-mediated immunity.

FIG. 21 shows the evaluation results of modified WT1₁₈₇ peptides on the activity of inducing specific cell-mediated immunity.

FIG. 22 shows the evaluation results of modified WT1₁₈₇ peptides on the activity of inducing specific cell-mediated immunity.

FIG. 23 shows the evaluation results of modified WT1₁₂₆ peptides on the activity of inducing specific cell-mediated immunity.

FIG. 24 shows the evaluation results of modified WT1₁₂₆ peptides on the activity of inducing specific cell-mediated immunity.

FIG. 25 shows the evaluation results of modified WT1₁₂₆ peptides on the activity of inducing specific cell-mediated immunity.

FIG. 26 shows the evaluation results of modified WT1₁₂₆ peptides on the activity of inducing specific cell-mediated immunity.

FIG. 27 shows the evaluation results of modified WT1₁₂₆ peptides on the activity of inducing specific cell-mediated immunity.

FIG. 28 shows the evaluation results of modified WT1₁₈₇ peptides on the activity of inducing specific cell-mediated immunity.

FIG. 29 shows the evaluation results of modified WT1₁₈₇ peptides on the activity of inducing specific cell-mediated immunity.

FIG. 30 shows the evaluation results of modified WT1₁₂₆ peptides on the activity of inducing specific cell-mediated immunity.

FIG. 31 shows the evaluation results of modified WT1₁₂₆ peptides on the activity of inducing specific cell-mediated immunity.

FIG. 32 shows the evaluation results of modified WT1₁₂₆ peptides on the activity of inducing specific cell-mediated immunity.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be illustrated.

The following codes are used when amino acid residues are abbreviated in this description and drawings.

-   Ala or A: Alanine residue -   Arg or R: Arginine residue -   Asn or N: Asparagine residue -   Asp or D: Aspartic acid residue -   Cys or C: Cysteine residue -   Gln or Q: Glutamine residue -   Glu or E: Glutamic acid residue -   Gly or G: Glycine residue -   His or H: Histidine residue -   Ile or I: Isoleucine residue -   Leu or L: Leucine residue -   Lys or K: Lysine residue -   Met or M: Methionine residue -   Phe or F: Phenylalanine residue -   Pro or P: Proline residue -   Ser or S: Serine residue -   Thr or T: Threonine residue -   Trp or W: Tryptophan residue -   Tyr or Y: Tyrosine residue -   Val or V: Valine residue

The WT1 protein of the present invention may be a gene product of a zinc finger-type transcription factor isolated as a causative gene of Wilms' tumor, the gene product being capable of binding to an HLA-A*0206 molecule and thereby serving as a target antigen of malignant tumors. More specifically, the WT1 protein of the present invention is preferably the human WT1 protein consisting of 449 amino acids (Sequence list: SEQ ID NO: 1) or a protein which consists of an amino acid sequence comprising deletion, substitution or addition of one to several amino acids (preferably about 2 to 6 amino acids) in the amino acid sequence of the human WT1 protein, and which is immunogenic in HLA-A*0206-positive persons. The amino acid used for addition or substitution may be a non-natural amino acid besides 20 gene-encoded amino acids.

The partial peptide of the WT1 protein (WT1 peptide) refers to a peptide consisting of a part of the amino acid sequence that constitutes the WT1 protein. The WT1 peptide may be a peptide which consists of 8 to 12 amino acids, preferably 8 to 9 amino acids derived from the WT1 protein and which binds to an HLA-A*0206 molecule and thereby induces cytotoxic T cells. Particularly preferred is the WT1₁₈₇ peptide (Ser Leu Gly Glu Gln Gln Tyr Ser Val; SEQ ID NO: 2) or the WT1₁₂₆ peptide (Arg Met Phe Pro Asn Ala Pro Tyr Leu; SEQ ID NO: 3), both described in the WO 00/06602 pamphlet.

A modified peptide comprising deletion, substitution or addition of one or several amino acids of the WT1 peptide can also be used as the WT1 peptide of the present invention as long as it is immunogenic in HLA-A*0206-positive persons. Examples of such a modified peptide include a modified WT1₁₈₇ peptide and a modified WT1₁₂₆ peptide.

The modified WT1₁₈₇ peptide is preferably a peptide comprising the same amino acid residues (EQQYS (SEQ ID NO: 76)) at positions 4 to 8 from the N terminus as the WT1₁₈₇ peptide has at the corresponding positions, and more preferably a peptide comprising the same amino acid residues (EQQYSV (SEQ ID NO: 77)) at positions 4 to 9 from the N terminus as the WT1₁₈₇ peptide has at the corresponding positions. Such a modified WT1₁₈₇ peptide is preferably a peptide consisting of any of the following amino acid sequences of SEQ ID NO: 4 to 26 and 54 to 62.

(GLGEQQYSV; SEQ ID NO: 4) WT1₁₈₇P1G peptide (ALGEQQYSV; SEQ ID NO: 5) WT1₁₈₇P1A peptide (VLGEQQYSV; SEQ ID NO: 6) WT1₁₈₇P1V peptide (LLGEQQYSV; SEQ ID NO: 7) WT1₁₈₇P1L peptide (ILGEQQYSV; SEQ ID NO: 8) WT1₁₈₇P1I peptide (MLGEQQYSV; SEQ ID NO: 9) WT1₁₈₇P1M peptide (WLGEQQYSV; SEQ ID NO: 10) WT1₁₈₇P1W peptide (FLGEQQYSV; SEQ ID NO: 11) WT1₁₈₇P1F peptide (YLGEQQYSV; SEQ ID NO: 12) WT1₁₈₇P1Y peptide (SVGEQQYSV; SEQ ID NO: 13) WT1₁₈₇P2V peptide (SQGEQQYSV; SEQ ID NO: 14) WT1₁₈₇P2Q peptide (SIGEQQYSV; SEQ ID NO: 15) WT1₁₈₇P2I peptide (SMGEQQYSV; SEQ ID NO: 16) WT1₁₈₇P2M peptide (SLLEQQYSV; SEQ ID NO: 17) WT1₁₈₇P3L peptide (SLAEQQYSV; SEQ ID NO: 18) WT1₁₈₇P3A peptide (SLVEQQYSV; SEQ ID NO: 19) WT1₁₈₇P3V peptide (SLMEQQYSV; SEQ ID NO: 20) WT1₁₈₇P3M peptide (SLPEQQYSV; SEQ ID NO: 21) WT1₁₈₇P3P peptide (SLWEQQYSV; SEQ ID NO: 22) WT1₁₈₇P3W peptide (SLFEQQYSV; SEQ ID NO: 23) WT1₁₈₇P3F peptide (SLYEQQYSV; SEQ ID NO: 24) WT1₁₈₇P3Y peptide (SLSEQQYSV; SEQ ID NO: 25) WT1₁₈₇P3S peptide (SLIEQQYSV; SEQ ID NO: 26) WT1₁₈₇P3I peptide (SLGEQQYSL; SEQ ID NO: 53) WT1₁₈₇P9L peptide (DLGEQQYSV; SEQ ID NO: 54) WT1₁₈₇P1D peptide (ELGEQQYSV; SEQ ID NO: 55) WT1₁₈₇P1E peptide (HLGEQQYSV; SEQ ID NO: 56) WT1₁₈₇P1H peptide (KLGEQQYSV; SEQ ID NO: 57) WT1₁₈₇P1K peptide (NLGEQQYSV; SEQ ID NO: 58) WT1₁₈₇P1N peptide (PLGEQQYSV; SEQ ID NO: 59) WT1₁₈₇P1P peptide (QLGEQQYSV; SEQ ID NO: 60) WT1₁₈₇P1Q peptide (RLGEQQYSV; SEQ ID NO: 61) WT1₁₈₇P1R peptide (TLGEQQYSV; SEQ ID NO: 62) WT1₁₈₇P1T peptide

The modified WT1₁₂₆ peptide is preferably a peptide comprising the same amino acid residues (PNAPY (SEQ ID NO: 78)) at positions 4 to 8 from the N terminus as the WT1₁₂₆ peptide has at the corresponding positions. Such a modified WT1₁₂₆ peptide is preferably a peptide consisting of any of the following amino acid sequences of SEQ ID NO: 27 to 52 and 63 to 75.

(GMFPNAPYL; SEQ ID NO: 27) WT1₁₂₆P1G peptide (AMFPNAPYL; SEQ ID NO: 28) WT1₁₂₆P1A peptide (VMFPNAPYL; SEQ ID NO: 29) WT1₁₂₆P1V peptide (LMFPNAPYL; SEQ ID NO: 30) WT1₁₂₆P1L peptide (IMFPNAPYL; SEQ ID NO: 31) WT1₁₂₆P1I peptide (MMFPNAPYL; SEQ ID NO: 32) WT1₁₂₆P1M peptide (WMFPNAPYL; SEQ ID NO: 33) WT1₁₂₆P1W peptide (FMFPNAPYL; SEQ ID NO: 34) WT1₁₂₆P1F peptide (YMFPNAPYL; SEQ ID NO: 35) WT1₁₂₆P1Y peptide (RVFPNAPYL; SEQ ID NO: 36) WT1₁₂₆P2V peptide (RQFPNAPYL; SEQ ID NO: 37) WT1₁₂₆P2Q peptide (RAFPNAPYL; SEQ ID NO: 38) WT1₁₂₆P2A peptide (RLFPNAPYL; SEQ ID NO: 39) WT1₁₂₆P2L peptide (RIFPNAPYL; SEQ ID NO: 40) WT1₁₂₆P2I peptide (RMIPNAPYL; SEQ ID NO: 41) WT1₁₂₆P3I peptide (RMLPNAPYL; SEQ ID NO: 42) WT1₁₂₆P3L peptide (RMGPNAPYL; SEQ ID NO: 43) WT1₁₂₆P3G peptide (RMAPNAPYL; SEQ ID NO: 44) WT1₁₂₆P3A peptide (RMVPNAPYL; SEQ ID NO: 45) WT1₁₂₆P3V peptide (RMMPNAPYL; SEQ ID NO: 46) WT1₁₂₆P3M peptide (RMPPNAPYL; SEQ ID NO: 47) WT1₁₂₆P3P peptide (RMWPNAPYL; SEQ ID NO: 48) WT1₁₂₆P3W peptide (RMFPNAPYV; SEQ ID NO: 49) WT1₁₂₆P9V peptide (RMFPNAPYA; SEQ ID NO: 50) WT1₁₂₆P9A peptide (RMFPNAPYI; SEQ ID NO: 51) WT1₁₂₆P9I peptide (RMFPNAPYM; SEQ ID NO: 52) WT1₁₂₆P9M peptide (DMFPNAPYL; SEQ ID NO: 63) WT1₁₂₆P1D peptide (EMFPNAPYL; SEQ ID NO: 64) WT1₁₂₆P1E peptide (HMFPNAPYL; SEQ ID NO: 65) WT1₁₂₆P1H peptide (KMFPNAPYL; SEQ ID NO: 66) WT1₁₂₆P1K peptide (NMFPNAPYL; SEQ ID NO: 67) WT1₁₂₆P1N peptide (PMFPNAPYL; SEQ ID NO: 68) WT1₁₂₆P1P peptide (QMFPNAPYL; SEQ ID NO: 69) WT1₁₂₆P1Q peptide (SMFPNAPYL; SEQ ID NO: 70) WT1₁₂₆P1S peptide (TMFPNAPYL; SEQ ID NO: 71) WT1₁₂₆P1T peptide (RIFPNAPYI; SEQ ID NO: 72) WT1₁₂₆P2I&P9I peptide (RIFPNAPYV; SEQ ID NO: 73) WT1₁₂₆P2I&P9V peptide (RLFPNAPYI; SEQ ID NO: 74) WT1₁₂₆P2L&P9I peptide (RLFPNAPYV; SEQ ID NO: 75) WT1₁₂₆P2L&P9V peptide

Inter alia, the modified WT1₁₈₇ peptide is preferably the WT1₁₈₇P1F peptide (SEQ ID NO: 11), the WT1₁₈₇P2M peptide (SEQ ID NO: 16) or the WT1₁₈₇P3M peptide (SEQ ID NO: 20), more preferably the WT1₁₈₇P1F peptide or the WT1₁₈₇P2M peptide, and still more preferably the WT1₁₈₇P2M peptide. The modified WT1₁₂₆ peptide is preferably the WT1₁₂₆P1F peptide (SEQ ID NO: 34), the WT1₁₂₆P2L peptide (SEQ ID NO: 39), the WT1₁₂₆P3M peptide (SEQ ID NO: 46) or the WT1₁₂₆P9V peptide (SEQ ID NO: 49), more preferably the WT1₁₂₆P2L peptide, the WT1₁₂₆P3M peptide or the WT1₁₂₆P9V peptide, and still more preferably the WT1₁₂₆P9V peptide.

The WT1 peptide in the cancer vaccine composition of the present invention is preferably the WT1₁₈₇ peptide, the WT1₁₂₆ peptide, the WT1₁₈₇P1F peptide, the WT1₁₈₇P2M peptide, the WT1₁₈₇P3M peptide, the WT1₁₂₆P1F peptide, the WT1₁₂₆P2L peptide, the WT1₁₂₆P3M peptide or the WT1₁₂₆P9V peptide. More preferred is the WT1₁₈₇ peptide, the WT1₁₂₆ peptide, the WT1₁₈₇P1F peptide, the WT1₁₈₇P2M peptide, the WT1₁₂₆P2L peptide, the WT1₁₂₆P3M peptide or the WT1₁₂₆P9V peptide. Even preferred is the WT1₁₈₇ peptide, the WT1₁₂₆ peptide, the WT1₁₈₇P2M peptide or the WT1₁₂₆P9V peptide. Particularly preferred is the WT1₁₈₇ peptide or the WT1₁₂₆ peptide.

A derivative of the WT1 peptide can also be used as the WT1 peptide. For example, the derivative of the WT1₁₈₇ or WT1₁₂₆ peptide may be formed of an amino acid sequence of the above-mentioned 9 contiguous amino acids and various substances bound to the N and/or C terminus thereof. The various substances may be, for example, amino acids, peptides, analogs thereof, etc. Such a substance bound to the WT1₁₈₇ peptide, the WT1₁₂₆ peptide or a modified peptide thereof undergoes, for example, in vivo enzyme treatment through intracellular processing etc., and finally the peptide consisting of the above-mentioned 9 amino acids is produced and presented as a complex with an HLA-A*0206 molecule on the cell surface. Thus, a WT1-specific CTL response can be induced in patients with HLA-A*0206.

The WT1 peptide can be prepared by a method usually used in the technical field, such as a peptide synthesis method described in Peptide Synthesis, Interscience, New York, 1966; The Proteins, Vol. 2, Academic Press Inc., New York, 1976; Peptide synthesis, Maruzen Co., Ltd., 1975; Basis and Experiments of Peptide Synthesis, Maruzen Co., Ltd. 1985; the Sequel to Development of Pharmaceuticals, Vol. 14 (peptide synthesis), Hirokawa Publishing Company, 1991; etc.

As a method of screening for the WT1 peptide and a modified peptide thereof, for example, a method involving conducting the IFNγ assay under single stimulation of, with a peptide, PBMCs (peripheral blood mononuclear cells) of some patients having HLA-A*0206, and then selecting a peptide showing a good response, is preferred because of simplicity.

In the present invention, polynucleotides, such as DNA encoding the above-mentioned WT1 protein or WT1 peptide immunogenic in HLA-A*0206-positive persons, can also be used as an active ingredient of the cancer vaccine composition. Namely, by inserting a polynucleotide encoding the WT1 protein or WT1 peptide into a suitable vector, preferably an expression vector, and then administering the vector into animals including humans, cancer immunity can be produced in the living body. Examples of the polynucleotide include DNA, RNA and the like, and preferred is DNA or RNA. The base sequence of the polynucleotide can be determined based on the amino acid sequence of the WT1 protein or WT1 peptide immunogenic in HLA-A*0206-positive persons. The polynucleotide can be prepared by a known DNA or RNA synthesis method, the PCR method, etc. Such a cancer vaccine composition for HLA-A*0206-positive persons, comprising DNA encoding the WT1 protein or WT1 peptide is also one aspect of the present invention. The WT1 protein or WT1 peptide is preferably a WT1 peptide, more preferably the WT1₁₈₇ peptide, the WT1₁₂₆ peptide or a modified peptide thereof, and most preferably the WT1₁₈₇ peptide or the WT1₁₂₆ peptide. The expression vector used to insert the above-mentioned DNA into is not particularly limited. RNA does not have to be inserted into a vector and can be used as it is as an active ingredient of the composition.

The cancer vaccine composition of the present invention can comprise an adjuvant. The adjuvant is not limited as long as, after administered together with or separately from the WT1 protein or WT1 peptide used as an antigen, it can nonspecifically enhance immunological responses to the antigen. Examples of the adjuvant include precipitating-type adjuvants and oily adjuvants. Examples of the precipitating-type adjuvant include sodium hydroxide, aluminum hydroxide, calcium phosphate, aluminum phosphate, alum, PEPES and carboxyvinyl polymers. A preferable oily adjuvant is one that can form micelles so that oil encloses an aqueous solution of an antigen. Specific examples thereof include liquid paraffin, lanolin, Freund, Montanide ISA-763AVG, Montanide ISA-51, incomplete Freund's adjuvant and complete Freund's adjuvant. These adjuvants can also be used as a mixture of two or more kinds thereof. Preferred is an oily adjuvant.

The amount of the adjuvant in the cancer vaccine composition of the present invention is not particularly limited as long as immunological responses to antigens can be nonspecifically enhanced. The amount thereof may be suitably selected depending on the kind of the adjuvant, etc.

The cancer vaccine composition of the present invention can be administered orally or parenterally (for example, intraperitoneally, subcutaneously, intracutaneously, intramuscularly, intravenously, intranasally, etc.). In the case of parenteral administration, an active ingredient, i.e., the WT1 protein or WT1 peptide, may also be percutaneously absorbed by applying the vaccine composition to the skin, or by attaching to the skin a patch containing the vaccine composition. The vaccine composition of the present invention can also be administered via inhaling etc. The vaccine composition is administered preferably parenterally, and more preferably intracutaneously or subcutaneously. The body part for intracutaneous or subcutaneous administration is preferably the upper arm etc., for example.

The cancer vaccine composition of the present invention can be in various dosage forms depending on its administration route, and exemplary dosage forms thereof include a solid preparation and a liquid preparation. The cancer vaccine composition may be, for example, in the form of a solid or liquid preparation to be used internally for oral administration, an injection for parenteral administration, or the like.

Examples of the solid preparation to be used internally for oral administration include tablets, pills, capsules, powders and granules.

For preparation of the solid preparation to be used internally, the WT1 protein or WT1 peptide is untreated, mixed with an additive, or granulated (according to, for example, stirring granulation, fluidized bed granulation, dry granulation, rolling stirring fluidized bed granulation, etc.), and then is subjected to a usual method. For example, the capsules can be prepared by encapsulation etc. and the tablets can be prepared by tableting etc. One or two kinds or more of the additives may be appropriately incorporated into the solid preparation. Examples of the additive include excipients such as lactose, mannitol, glucose, microcrystalline cellulose and corn starch; binders such as hydroxypropylcellulose, polyvinylpyrrolidone and magnesium aluminometasilicate; dispersing agents such as corn starch; disintegrators such as calcium carboxymethyl cellulose; lubricants such as magnesium stearate; solubilizing agents such as glutamic acid and aspartic acid; stabilizers; water soluble polymers including celluloses such as hydroxypropylcellulose, hydroxypropylmethylcellulose and methylcellulose, and synthetic polymers such as polyethylene glycol, polyvinylpyrrolidone and polyvinyl alcohol; and sweeteners such as white sugar, powder sugar, sucrose, fructose, glucose, lactose, reduced malt sugar syrup (maltitol syrup), reduced malt sugar syrup powder (maltitol syrup powder), high-glucose corn syrup, high-fructose corn syrup, honey, sorbitol, maltitol, mannitol, xylitol, erythritol, aspartame, saccharin and saccharin sodium.

The granules or tablets may be covered with a coating agent etc. if needed, and may be covered with two or more layers thereof. Examples of the coating agent include white sugar, gelatin, hydroxypropyl cellulose and hydroxypropylmethylcellulose phthalate. The capsules can be prepared by mixing the active ingredient with pranlukast hydrate and an excipient appropriately selected from the above excipients, optionally granulating the mixture, and optionally covering the resulting granules with a coating agent, followed by capsule filling. Alternatively, the capsules can be prepared by adding glycerol, sorbitol, etc. to an appropriate capsule base (gelatin etc.) to increase its plasticity, and encapsulating the active ingredient with the resulting base. To the capsule base may be added a colorant or a preservative (sulfur dioxide; and parabens such as methyl parahydroxybenzoate, ethyl parahydroxybenzoate and propyl parahydroxybenzoate) if needed. The capsules include hard capsules and soft capsules.

Examples of the liquid preparation to be used internally for oral administration include waters, suspensions/emulsions, syrups, preparations to be dissolved before use such as dry syrups, and elixirs. For preparation of the liquid preparation to be used internally, the WT1 protein or WT1 peptide is dissolved, suspended or emulsified in a diluent generally used for liquid preparations to be used internally. Examples of the diluent include purified water, ethanol and a mixture thereof. The liquid preparation may further contain a wetting agent, a suspending agent, an emulsifier, a sweetener, a flavoring, a fragrance, a preservative or a buffering agent. The dry syrups can be prepared, for example, by mixing the active ingredient with pranlukast hydrate and an additional ingredient such as white sugar, powder sugar, sucrose, fructose, glucose and lactose. The dry syrups may also be made into granules in a usual manner.

Examples of the dosage form for parenteral administration include injections, ointments, gels, creams, patches, aerosols and sprays. Preferred are injections. For example, the injection preferably contains a conventional carrier with the WT1 protein or WT1 peptide.

The injection for parenteral administration may be an aqueous injection or an oily injection. The aqueous injection can be prepared according to a known method, for example, by appropriately adding a pharmaceutically acceptable additive to an aqueous solvent (water for injection, purified water, etc.) to make a solution, mixing the WT1 protein or WT1 peptide with the solution, filter sterilizing the resulting mixture with a filter etc., and then filling an aseptic container with the resulting filtrate. Examples of the pharmaceutically acceptable additive include the above-mentioned adjuvants; isotonizing agents such as sodium chloride, potassium chloride, glycerol, mannitol, sorbitol, boric acid, borax, glucose and propylene glycol; buffering agents such as a phosphate buffer solution, an acetate buffer solution, a borate buffer solution, a carbonate buffer solution, a citrate buffer solution, a Tris buffer solution, a glutamate buffer solution and an epsilon-aminocaproate solution; preservatives such as methyl parahydroxybenzoate, ethyl parahydroxybenzoate, propyl parahydroxybenzoate, butyl parahydroxybenzoate, chlorobutanol, benzyl alcohol, benzalkonium chloride, sodium dehydroacetate, sodium edetate, boric acid and borax; thickeners such as hydroxyethylcellulose, hydroxypropylcellulose, polyvinyl alcohol and polyethylene glycol; stabilizers such as sodium hydrogen sulfite, sodium thiosulfate, sodium edetate, sodium citrate, ascorbic acid and dibutyl hydroxy toluene; and pH adjusters such as hydrochloric acid, sodium hydroxide, phosphoric acid and acetic acid. The injection may further contain an appropriate solubilizing agent, and examples thereof include alcohols such as ethanol; polyalcohols such as propylene glycol and polyethylene glycol; and non-ionic surfactants such as polysorbate 80, polyoxyethylene hydrogenated castor oil 50, lysolecithin and pluronic polyols. Also, proteins such as bovine serum albumin and keyhole limpet hemocyanin; polysaccharides such as aminodextran; etc. may be contained in the injection. For preparation of the oily injection, for example, sesame oil or soybean oil is used as an oily solvent, and benzyl benzoate or benzyl alcohol may be blended as a solubilizing agent. The prepared injection is usually stored in an appropriate ampule, vial, etc. The liquid preparations, such as injections, can also be deprived of moisture and preserved by cryopreservation or lyophilization. The lyophilized preparations become ready to use by redissolving them in added distilled water for injection etc. just before use.

Another dosage form of the cancer vaccine composition of the present invention may be a liposome containing the WT1 protein or WT1 peptide and, if needed, polysaccharides and/or other ingredients that can be blended into the cancer vaccine composition.

The dose of the cancer vaccine composition of the present invention varies with the kind of the WT1 protein, WT1 peptide or DNA to be used, the age and body weight of the patient, the disease to be treated, etc. For example, in the case of the vaccine composition comprising the WT1 peptide, for example the WT1₁₈₇ peptide or the WT1₁₂₆ peptide, the daily dose is preferably about 0.1 μg/kg bw to 1 mg/kg bw as the amount of the WT1 peptide. The dose of the WT1 peptide is usually 0.0001 mg to 1000 mg, preferably 0.01 mg to 1000 mg, and more preferably 0.1 mg to 10 mg. This amount is preferably administered once in several days to several months.

The cancer vaccine composition of the present invention is a cancer vaccine composition for HLA-A*0206-positive persons. The HLA type, which is a measure for selecting HLA-A*0206-positive persons, can be determined from, for example, donors' peripheral blood. Examples of the method of determining the HLA type include known methods, such as the DNA typing method, for example, the SBT (Sequencing Based Typing) method or the SSP method, and the HLA typing method. In the SBT method, the base sequence of a PCR-amplified DNA is compared with the base sequence data of the known alleles to precisely identify the HLA gene type. In the SSP method, after PCR amplification using a variety of primers specific to respective HLA alleles, subsequent electrophoresis is performed to check a positive band. Thus, the HLA gene type can be identified.

When the cancer vaccine composition of the present invention has been administered into an HLA-A*0206-positive person, the HLA-A*0206-restricted WT1 protein or WT1 peptide in the vaccine composition, or the WT1 protein or WT1 peptide expressed from DNA or RNA in the vaccine composition binds to an HLA-A*0206 molecule on the surface of an antigen presenting cell (dendritic cell) of the HLA-A*0206-positive person. This induces specific antitumor immunity, i.e., WT1-specific CTLs, which destroy cancer cells in the subject (HLA-A*0206-positive person). Such antitumor immunity can be checked, for example by the WT1-specific CTL response, the cytotoxicity test against cancer cells (for example, ⁵¹Cr release cytotoxicity test), etc. For example, the HLA-A*0201-restricted WT1₁₈₇ peptide and WT1₁₂₆ peptide each consisting of 9 amino acids derived from the WT1 protein, which have been reported to be capable of inducing a WT1-specific CTL response, can induce an HLA-A*0206-restricted response. About 17% of Japanese people are HLA-A*0206-positive, while almost the same proportion are HLA-A*0201-positive. In the following Examples 1 to 5, WT1₁₈₇ peptide-specific CTLs were prepared from PBMCs of three HLA-A*0206-positive blood donors. The induced CTLs showed the cytotoxic effect on WT1-expressing, HLA-A*0206-positive leukemia cells. Since WT1₁₈₇ peptide- and WT1₁₂₆ peptide-specific CTL activity can be inhibited by an anti-HLA class I antibody, the activity is found to be exhibited by HLA class I-restricted CTLs. The WT1 protein or WT1 peptide including the WT1₁₈₇ peptide and/or the WT1₁₂₆ peptide, or a modified peptide thereof can be a vaccine for HLA-A*0206-positive cancer patients as well as HLA-A*0201-positive cancer patients. Therefore, the immunotherapy based on the WT1 protein or WT1 peptide for patients with malignant tumors, such as hematopoietic tumors and solid cancers, can be applied further to HLA-A*0206-positive cancer patients. The method of cancer treatment and/or prevention in HLA-A*0206-positive persons, comprising administering the cancer vaccine composition of the present invention into an HLA-A*0206-positive person, is one of preferable embodiments of the present invention.

In HLA-A*0206-positive persons, the cancer vaccine composition of the present invention can be used for treatment and/or prevention of cancers accompanied by increased expression of the WT1 gene: for example, hematopoietic tumors such as leukemia, myelodysplastic syndrome, multiple myeloma and malignant lymphoma; and solid cancers such as gastric cancer, colon cancer, lung cancer, breast cancer, germ cell cancer, hepatic cancer, skin cancer, bladder cancer, prostate cancer, uterine cancer, cervical cancer and ovarian cancer.

An exemplary administration method of the cancer vaccine composition of the present invention is a method comprising collecting PBMCs from peripheral blood of an HLA-A*0206-positive patient, extracting dendritic cells from the PBMCs, pulsing the dendritic cells with a peptide, for example the WT1₁₈₇ peptide or the WT1₁₂₆ peptide, or a polynucleotide, for example DNA or RNA, contained as an active ingredient in the cancer vaccine composition of the present invention, and returning the dendritic cells to the patient via subcutaneous administration etc. The conditions for pulsing dendritic cells with the WT1 peptide etc. are not particularly limited as long as the effect of the present invention is achieved, and may be ordinary conditions.

In the case where RNA encoding the WT1 protein or WT1 peptide is used for the cancer vaccine composition, it is preferable that the composition is administered so that the RNA is introduced into dendritic cells of an HLA-A*0206-positive person. An exemplary method for introducing RNA into dendritic cells of an HLA-A*0206-positive person is a method comprising collecting dendritic cells from an HLA-A*0206-positive person in the same manner as mentioned above, and introducing RNA into the dendritic cells with an electric pulse. The WT1 protein or WT1 peptide expressed from the introduced RNA in the dendritic cells is allowed to be presented on the surface thereof. By returning the dendritic cells pulsed with the RNA into the HLA-A*0206-positive person, cancer immunity can be quickly produced in the living body. Such a method of cancer treatment or prevention, comprising introducing RNA encoding the WT1 protein or WT1 peptide into dendritic cells of an HLA-A*0206-positive person, is one of preferable embodiments of the present invention.

Another embodiment of the present invention relates to a method for inducing WT1-specific CTLs, by culturing, in the presence of the WT1 protein or WT1 peptide, PBMCs derived from an HLA-A*0206-positive person, to obtain WT1-specific CTLs induced therefrom. The subject from which PBMCs are derived is not particularly limited as long as the subject is HLA-A*0206-positive. Examples of the WT1 protein or WT1 peptide include the WT1₁₈₇ peptide, the WT1₁₂₆ peptide and a modified peptide thereof, and preferably the WT1₁₈₇ peptide and the WT1₁₂₆ peptide. For example, WT1-specific CTLs can be induced from CTL precursor cells among PBMCs by culturing PBMCs derived from an HLA-A*0206-positive person in the presence of the WT1₁₈₇ peptide (or WT1₁₂₆ peptide). The culture conditions for PBMCs derived from an HLA-A*0206-positive person is not particularly limited, and may be ordinary conditions. The thus-obtained CTLs recognize a complex of the WT1₁₈₇ peptide (or the WT1₁₂₆ peptide) and an HLA-A*0206 molecule. Therefore, by use of WT1-specific CTLs induced according to the present invention, WT1-highly-expressing tumor cells can be specifically destroyed in an HLA-A*0206-positive person, and thereby hematopoietic tumors and solid cancers in the subject, i.e., an HLA-A*0206-positive person, can be treated and/or prevented. The method for administering such WT1-specific CTLs into an HLA-A*0206-positive subject is not particularly limited, and for example, may be the same as the administration method of the above-mentioned cancer vaccine composition.

Another embodiment of the present invention relates to a kit for inducing WT1-specific CTLs, comprising the HLA-A*0206-restricted WT1 protein or WT1 peptide as an essential constituent. Preferably, the kit is used for the above-mentioned method for inducing WT1-specific CTLs derived from an HLA-A*0206-positive person. Such a kit may comprise, for example, a means for collecting PBMCs, an adjuvant and a reaction container in addition to the HLA-A*0206-restricted WT1 protein or WT1 peptide. By use of the kit, WT1-specific CTLs that recognize a complex of a cancer antigen, such as the WT1₁₈₇ peptide and the WT1₁₂₆ peptide, and an HLA-A*0206 molecule can be efficiently induced.

Another embodiment of the present invention relates to a method for inducing dendritic cells that present the WT1 protein or WT1 peptide, by culturing, in the presence of the WT1 protein or WT1 peptide, immature dendritic cells derived from an HLA-A*0206-positive person, to obtain dendritic cells induced therefrom which present the WT1 protein or WT1 peptide. Examples of the WT1 protein or WT1 peptide include the WT1₁₈₇ peptide, the WT1₁₂₆ peptide and a modified peptide thereof, and preferably the WT1₁₈₇ peptide and the WT1₁₂₆ peptide. The subject from which immature dendritic cells are derived is not particularly limited as long as the subject is HLA-A*0206-positive. Since immature dendritic cells are present among PBMCs etc., PBMCs may also be cultured in the presence of the WT1₁₈₇ peptide or the WT1₁₂₆ peptide, for example. By administration of the thus-obtained dendritic cells to an HLA-A*0206-positive person, the above-mentioned WT1-specific CTLs are efficiently induced, and thereby hematopoietic tumors and solid cancers in the subject can be treated and/or prevented. The method for administering such dendritic cells into an HLA-A*0206-positive subject is not particularly limited, and for example, may be the same as the administration method of the above-mentioned cancer vaccine composition.

Another embodiment of the present invention relates to a kit for inducing dendritic cells that present the WT1 protein or WT1 peptide, comprising the HLA-A*0206-restricted WT1 protein or WT1 peptide as an essential constituent. Preferably, the kit is used for the above-mentioned method for inducing dendritic cells. Such a kit may comprise, for example, a means for collecting immature dendritic cells and PBMCs, an adjuvant and a reaction container in addition to the HLA-A*0206-restricted WT1 protein or WT1 peptide. By use of the kit, dendritic cells that present the WT1 protein or WT1 peptide via an HLA-A*0206 molecule can be efficiently induced.

Cancers in HLA-A*0206-positive persons can be diagnosed by use of

-   (1) the WT1 protein or WT1 peptide, WT1-specific CTLs induced by the     above-mentioned method, or dendritic cells induced by the     above-mentioned method, or -   (2) an antibody against the following: the WT1 protein or WT1     peptide, WT1-specific CTLs induced by the above-mentioned method, or     dendritic cells induced by the above-mentioned method.     Such a method of cancer diagnosis is also one aspect of the present     invention. In the above (1), cancer diagnosis is conducted     preferably using WT1-specific CTLs induced by above-mentioned     method. Examples of the WT1 protein or WT1 peptide include the     WT1₁₈₇ peptide, the WT1₁₂₆ peptide and a modified peptide thereof,     and preferably the WT1₁₈₇ peptide and the WT1₁₂₆ peptide.

According to the present invention, an exemplary method of cancer diagnosis for HLA-A*0206-positive persons comprises a step of detecting or quantifying the WT1 protein or WT1 peptide, an antibody thereagainst or WT1-specific CTLs in a sample from an HLA-A*0206-positive person, and a step of comparing the amount of the protein or a partial peptide thereof, an antibody thereagainst or the WT1-specific CTLs, with that in the case where cancer is not developed.

In a cancer patient sample (for example, blood), the WT1 peptide and/or WT1 protein released from cancer cells is present, and the immunological response against a cancer antigen is enhanced. That is, the cancer patient sample has an increased amount of an antibody against the WT1 peptide or WT1 protein, WT1-specific CTLs, etc. For this reason, when the amount of the WT1 peptide or WT1 protein, an antibody thereagainst or the WT1-specific CTLs in the sample is increased compared with that in the case where cancer is not developed, cancer may have been developed. The amount of the antibody can be measured by the ELISA method, for example. The WT1-specific CTLs can be detected by a method using WT1 multimers such as MHC tetramers described below.

Alternatively, cancer diagnosis can also be performed by incubating the above-mentioned CTLs, dendritic cells or antibody together with a sample from an HLA-A*0206-positive subject, or administering the above-mentioned CTLs, dendritic cells or antibody into an HLA-A*0206-positive subject; and then determining the position, region, amount, etc. of the CTLs, dendritic cells or antibody. Since CTLs and dendritic cells have a property to gather around cancer cells, cancer diagnosis can be performed by administering the CTLs or dendritic cells into the subject, and examining the position or region thereof. A method of cancer diagnosis for HLA-A*0206-positive persons, comprising a step of administering WT1-specific CTLs or dendritic cells induced by the above-mentioned method into an HLA-A*0206-positive subject, and a step of determining the position or region of the CTLs or dendritic cells in the HLA-A*0206-positive subject is also one aspect of the present invention.

Cancer diagnosis can also be performed by incubating CTLs or dendritic cells together with a sample from an HLA-A*0206-positive subject to allow them to react, adding an antibody against the CTLs or dendritic cells, continuing incubation, and detecting or quantifying an antibody-bound complex of the cancer cell and CTLs, antibody-bound dendritic cells, etc. via a label etc. bound to the antibody. When the amount of the antibody-bound complex of the cancer cell and CTLs or the antibody-bound dendritic cells is increased compared with that in the case where cancer is not developed, cancer may have been developed. The above-mentioned CTLs, dendritic cells or antibody may be labeled. The labeling enables the diagnosis to be efficiently performed. Examples of the sample from an HLA-A*0206-positive subject include biological specimens obtained from HLA-A*0206-positive persons, such as urine, blood, tissue extract fluid, saliva, tear and other body fluids, and blood is preferable.

Examples of the method of cancer diagnosis for HLA-A*0206-positive persons using the above-mentioned WT1 protein or WT1 peptide include the MHC tetramer assay, the MHC pentamer assay and the MHC dextramer assay, each of which uses the WT1 peptide as an antigen. For example, in the MHC tetramer assay or MHC pentamer assay using the WT1₁₈₇ peptide or WT1₁₂₆ peptide as an antigen peptide, WT1-specific CTLs in HLA-A*0206-positive persons can be detected by use of an MHC/WT1₁₈₇ peptide complex or an MHC/WT1₁₂₆ peptide complex as a probe. Since cancer patients show high expression of WT1-specific CTLs, cancer can be diagnosed by measuring the expression of WT1-specific CTLs in HLA-A*0206-positive persons. Since cancer patients manifest an enhanced immunological response against cancer antigens, cancer can be diagnosed also by examining immunological response against the WT1 protein or WT1 peptide in HLA-A*0206-positive persons. Examples of the method of examining immunological response include a method involving measuring an antibody against the WT1 protein or WT1 peptide by ELISA. Such a method of cancer diagnosis for HLA-A*0206-positive persons using a protein product of the tumor suppressor gene WT1 or a partial peptide thereof is also one aspect of the present invention. The MHC tetramer assay and MHC pentamer assay can be performed by a known method using a commercially available kit, for example, “WT1 tetramer” (Medical & Biological Laboratories, Co., Ltd.).

Cancer diagnosis for HLA-A*0206-positive persons can also be performed by a method comprising a step of reacting a sample from an HLA-A*0206-positive subject with an antibody against the following: the WT1 protein or WT1 peptide, WT1-specific CTLs induced by the above-mentioned method or dendritic cells induced by the above-mentioned, and a step of detecting or quantifying a complex of the antibody with the WT1 protein or WT1 peptide, or a complex of the antibody with WT1-specific CTLs or dendritic cells. When the amount of the complex of the antibody with the WT1 protein or WT1 peptide, or the complex of the antibody with WT1-specific CTLs or dendritic cells is increased compared with that in the case where cancer is not developed, cancer may have been developed.

Examples of the antibody against dendritic cells include an antibody which recognizes a WT1 peptide/HLA-A*0206 complex. Since such an antibody can recognize the WT1 peptide and an HLA-A*0206 molecule, the antibody can recognize dendritic cells having the WT1 peptide presented via HLA Class I.

An antibody which recognizes a complex of WT1 peptide/HLA-A*0206/TCR (T cell antigen receptor) of CTLs can also be used as the antibody against dendritic cells. Such an antibody can recognize a complex of a dendritic cell and a CTL, and a complex of a cancer cell and a CTL.

Cancer diagnosis can be performed by incubating such an antibody together with a sample from an HLA-A*0206-positive subject to allow them to form a complex, and detecting or quantifying an antibody-bound complex of the cancer cell and CTLs, antibody-bound dendritic cells presenting the WT1 peptide, or the like via the fluorescence emitted by the antibody. When the amount of the antibody-bound complex of the cancer cell and CTLs, the antibody-bound dendritic cells presenting the WT peptide, or the like is increased compared with that in the case where cancer is not developed, cancer may have been developed.

A method of cancer treatment or prevention, comprising administering a composition containing the WT1 protein or WT1 peptide into an HLA-A*0206-positive person, is also one aspect of the present invention. The composition comprising the WT1 protein or WT1 peptide and preferable embodiments thereof are the same as described regarding the above-mentioned cancer vaccine composition.

Use of the WT1 protein or WT1 peptide for cancer treatment or prevention in HLA-A*0206-positive persons, and use thereof for production of a cancer vaccine composition used for cancer treatment or prevention in HLA-A*0206-positive persons is also one aspect of the present invention. The WT1 protein or WT1 peptide and preferable embodiments thereof are the same as described regarding the above-mentioned cancer vaccine composition.

A cancer vaccine composition for HLA-A*0201-positive persons, comprising a modified peptide of the WT1₁₈₇ peptide (SEQ ID NO: 2) or the WT1₁₂₆ peptide (SEQ ID NO: 3), either of which is a partial peptide of a protein product of the tumor suppressor gene WT1, the modified peptide being immunogenic in HLA-A*0201-positive persons, is also one aspect of the present invention.

Examples of a modified WT1₁₈₇ peptide or a modified WT1₁₂₆ peptide include peptides comprising deletion, substitution or addition of one or several amino acids of the above-mentioned WT1₁₈₇ peptide or WT1₁₂₆ peptide. The modified WT1₁₈₇ peptide is preferably a peptide comprising the same amino acid residues at positions 4 to 8 from the N terminus as the WT1₁₈₇ peptide has at the corresponding positions. As such a modified peptide, preferred are the above-mentioned peptides of SEQ ID NOS: 4 to 12, 15 and 16, 18 to 20 and 22 to 25. The WT1₁₈₇P9L peptide (SLGEQQYSL; SEQ ID NO: 53) is also preferred. The modified WT1₁₂₆ peptide is preferably a peptide comprising the same amino acid residues at positions 4 to 8 from the N terminus as the WT1₁₂₆ peptide has at the corresponding positions. For example, preferred are the above-mentioned peptides of SEQ ID NOS: 27 to 37 and 39 to 52.

In yet another preferable embodiment of the present invention, the above-mentioned peptides of SEQ ID NOS: 4 to 26 and 53 to 62 may be used as a modified WT1₁₈₇ pep tide, and the above-mentioned peptides of SEQ ID NOS: 27 to 52 and 63 to 75 may be used as a modified WT1₁₂₆ peptide. Among the modified peptides of SEQ ID NOS: 4 to 75, the peptides except the WT1₁₈₇P1D peptide, the WT1₁₈₇P1E peptide, the WT1₁₈₇P1H peptide, the WT1₁₈₇P1P peptide and the WT1₁₈₇P2Q peptide; and the WT1₁₂₆P1D peptide, the WT1₁₂₆P1E peptide, the WT1₁₂₆P1P peptide, the WT1₁₂₆P2A peptide and the WT1₁₂₆P2Q peptide are preferred.

Inter alia, the modified WT1₁₈₇ peptide is preferably the WT1₁₈₇P1F peptide, the WT1₁₈₇P2M peptide or the WT1₁₈₇P3M peptide, and more preferably the WT1₁₈₇P1F peptide or the WT1₁₈₇P2M peptide. The modified WT1₁₂₆ peptide is preferably the WT1₁₂₆P1F peptide, the WT1₁₂₆P2L peptide, the WT1₁₂₆P3M peptide or the WT1₁₂₆P9V peptide, and more preferably the WT1₁₂₆P1F peptide or the WT1₁₂₆P2L peptide.

The amount for use of the modified WT1₁₈₇ pep tide or WT1₁₂₆ peptide which is immunogenic in HLA-A*0201-positive persons is the same as that of the WT1 peptide in the above-mentioned cancer vaccine composition for HLA-A*0206-positive persons. The other ingredients of the cancer vaccine composition for HLA-A*0201-positive persons and preferable embodiments thereof are the same as those of the above-mentioned vaccine composition for HLA-A*0206-positive persons.

DNA and RNA encoding the above-mentioned modified WT1₁₈₇ peptide or WT1₁₂₆ peptide which is immunogenic in HLA-A*0201-positive persons can also be used as an active ingredient of the cancer vaccine composition for HLA-A*0201-positive persons. Such a cancer vaccine composition for HLA-A*0201-positive persons is also one aspect of the present invention.

The other ingredients than the above-mentioned DNA and RNA in the cancer vaccine composition for HLA-A*0201-positive persons and preferable embodiments thereof are the same as those of the above-mentioned cancer vaccine composition for HLA-A*0206-positive persons.

WT1-specific CTLs can be induced from PBMCs derived from an HLA-A*0201-positive person by culturing the PBMCs in the presence of the modified WT1₁₈₇ peptide or WT1₁₂₆ peptide which is immunogenic in the above-mentioned HLA-A*0201-positive person. Such a method of inducing WT1-specific CTLs is also one aspect of the present invention.

Preferable examples of the modified WT1₁₈₇ peptide or WT1₁₂₆ peptide which is immunogenic in HLA-A*0201-positive persons are the same as used for the above-mentioned cancer vaccine composition for HLA-A*0201-positive persons.

Dendritic cells that present the modified WT1₁₈₇ peptide or WT1₁₂₆ peptide can be induced from immature dendritic cells derived from an HLA-A*0201-positive person by culturing the immature dendritic cells in the presence of the modified peptide which is immunogenic in the above-mentioned HLA-A*0201-positive person. Such a method for inducing dendritic cells that present the modified WT1₁₈₇ peptide or WT1₁₂₆ peptide is also one aspect of the present invention. Preferable examples of the modified peptide are the same as used for the above-mentioned cancer vaccine composition for HLA-A*0201-positive persons.

Cancers in HLA-A*0201-positive persons can be diagnosed by use of the above-mentioned modified WT1₁₈₇ peptide or modified WT1₁₂₆ peptide immunogenic in HLA-A*0201-positive persons, an antibody thereagainst, WT1-specific CTLs induced by the modified peptide or dendritic cells induced by the modified peptide. Such a method of cancer diagnosis for HLA-A 0201-positive persons is also one aspect of the present invention. The method of cancer diagnosis for HLA-A*0201-positive persons and preferable embodiments thereof are the same as the above-mentioned method of cancer diagnosis for HLA-A*0206-positive persons and preferable embodiments thereof.

Examples of the method of cancer diagnosis for HLA-A*0201-positive persons include the MHC tetramer assay, the MHC pentamer assay and the MHC dextramer assay, each of which uses the modified WT1₁₈₇ peptide or modified WT1₁₂₆ peptide immunogenic in HLA-A*0201-positive persons as an antigen. Preferable examples of the modified peptide are the same as used for the above-mentioned cancer vaccine composition for HLA-A*0201-positive persons.

Cancers in HLA-A*021-positive persons can be diagnosed by use of an antibody against the following: the above-mentioned modified WT1₁₈₇ peptide or modified WT1₁₂₆ peptide immunogenic in HLA-A*0201-positive persons, WT1-specific CTLs induced by the modified peptide or dendritic cells induced by the modified peptide. Such a method of cancer diagnosis for HLA-A*0201-positive persons is also one aspect of the present invention. Preferable examples of the modified peptide are the same as used for the above-mentioned cancer vaccine composition for HLA-A*0201-positive persons. The method of cancer diagnosis for HLA-A*0201-positive persons and preferable embodiments thereof are the same as the above-mentioned method of cancer diagnosis for HLA-A*0206-positive persons and preferable embodiments thereof.

A method of cancer treatment or prevention, comprising administering an HLA-A*0201-positive person a cancer vaccine composition containing the following peptide:

a modified peptide of the WT1₁₈₇ peptide (SEQ ID NO: 2) or the WT1₁₂₆ peptide (SEQ ID NO: 3), either of which is a partial peptide of a protein product of the tumor suppressor gene WT1, the modified peptide being immunogenic in HLA-A*0201-positive persons,

is also one aspect of the present invention.

Preferable examples of the modified peptide are the same as used for the above-mentioned cancer vaccine composition for HLA-A*0201-positive persons. The cancer vaccine composition and preferable embodiments thereof are the same as described regarding the above-mentioned vaccine composition for HLA-A*0201-positive persons.

The present invention relates to use of the following peptide:

a modified peptide of the WT1₁₈₇ peptide (SEQ ID NO: 2) or the WT1₁₂₆ peptide (SEQ ID NO: 3), either of which is a partial peptide of a protein product of the tumor suppressor gene WT1, the modified peptide being immunogenic in an HLA-A*0201-positive person, for cancer treatment or prevention in HLA-A*0201-positive persons, and use thereof for production of a cancer vaccine composition used for cancer treatment or prevention in HLA-A*0201-positive persons.

Preferable examples of the modified peptide are the same as used for the above-mentioned cancer vaccine composition for HLA-A*0201-positive persons. The cancer vaccine composition and preferable embodiments thereof are the same as described regarding the above-mentioned vaccine composition for HLA-A*0201-positive persons.

EXAMPLES

Hereinafter, the present invention will be illustrated in more detail by way of examples, but is not limited thereto. Abbreviations in Examples indicate the following meanings. Synthetic peptides were purchased from SIGMA GENOSYS JAPAN.

-   DCs: Dendritic cells -   PBMCs: Peripheral blood mononuclear cells -   CD: Cluster of Differentiation (leukocyte differentiation antigen) -   GM-CSF: Granulocyte monocyte colony stimulating factor -   IL: Interleukin -   TNFα: Tumor necrosis factor-α -   PGE: Prostaglandin -   Gy: Gray -   B-LCLs: B-lymphoblastoid cell line -   EB virus: Epstein-Barr virus -   tBu: t-butyl -   Trt: Triphenylmethyl -   Fmoc: 9-fluorenylmethyloxycarbonyl

Example 1 Prediction of HLA Molecules Capable of Binding with the WT1 Peptide

HLA molecules capable of binding with the WT1187 peptide (SEQ ID NO: 2) were predicted using the NetMHC2.0 Server-prediction program.

As a result, the HLA-A*0201-restricted WT1187 peptide capable of inducing WT1-specific CTLs was ranked high in terms of binding affinity to an HLA-A*0206 molecule in the NetMHC2.0 Server-prediction program.

Example 2 Preparation of WT1₁₈₇ Peptide-specific CTLs from PBMCs of HLA-A*0206-positive Healthy Blood Donors, and Cytotoxicity Test of the CTLs

(1) Separation of PBMCs of HLA-A*0206-positive Healthy Blood Donors, and Preparation of DCs

First, PBMCs were isolated from peripheral blood of each of HLA-A*0206 healthy blood donors (three persons) by Ficoll-Hypaque density gradient centrifugation. Then, CD14-positive cells were selected from the PBMCs using anti-human CD14 Magnetic Particles-DM (manufactured by Becton, Dickinson and company (BD)). In this case, it was considered that a large number of CD14-positive cells are present in the monocyte population. The selected CD14-positive cells were cultured in an X-VIVO15 medium (manufactured by BioWhittaker, Walkersville, Md.) supplemented with 1 v/v % human AB serum, 800 IU/mL GM-CSF (manufactured by Pepro Tech INC. Rocky Hill, N.J.) and 1000 IU/mL IL-4 (manufactured by Pepro Tech INC) to prepare DCs.

(2) Induction of Autologous Mature DCs

The DCs prepared in the above (1) were cultured at 37° C. for 1 day, and then a maturation cytokine cocktail containing 10 ng/mL TNFα (tumor necrosis factor-α; Pepro Tech INC, Rocky Hill, N.J.), 10 ng/mL IL-β, 1000 IU/mL IL-6 and 1 μg/mL PGE2 was added to culture wells containing the DCs. After 24 hour-culture at 37° C., autologous mature DCs were obtained.

(3) Induction of WT1₁₈₇ Peptide-specific CTLs

The autologous mature DCs were pulsed with the WT1₁₈₇ peptide, irradiated with 30 Gy of radiation, and co-cultured with CD8-positive T cell-enriched PBMCs obtained from the HLA-A*0206-positive healthy blood donor. The pulsing of the DCs with the WT1₁₈₇ peptide was performed by culturing the DCs in the presence of 10 μg/mL of the WT1₁₈₇ peptide at 37° C. for 30 minutes. The CD8-positive T cells were enriched from PBMCs of the HLA-A*0206-positive healthy blood donor using CD8 MicroBeads and MS column (manufactured by Miltenyi Biotec GmbH).

From the second stimulation, autologous PBMCs which had been pulsed with the peptide and then irradiated with radiation were used as selective stimulator cells. Two days after the second stimulation, recombinant IL-2 (provided by Shionogi & Co., Ltd.) and IL-7 (manufactured by Pepro Tech INC) were added to the culture medium at the concentrations of 10 IU/mL and 10 ng/mL, respectively. After the 4th stimulation, the cells were cultured for 10 days at 37° C. and then the resulting cells (CTLs) were collected by centrifugation using a centrifuge. The cytotoxic activity of these cells (CTLs) against target cells was examined by a ⁵¹Cr release cytotoxicity test.

(4) Cytotoxicity Test

The cytotoxicity test was performed by a ⁵¹Cr release cytotoxicity test. The ⁵¹Cr release cytotoxicity test was performed as follows. First, target cells (1×10⁷ cells/mL) were incubated in the presence of 100 μL of ⁵¹Cr (specific activity: 1 mCi/ml) in RPMI1640 (manufactured by NIHON PHARMACEUTICAL CO., LTD.) supplemented with 10% fetal bovine serum at 37° C. for 1.5 hours to label the target cells with ⁵¹Cr. Then, the ⁵¹Cr-labeled target cells were added to wells of 96 round-bottom well plates containing various numbers of CTLs obtained in the above (3) (suspended in 100 μL of an assay medium), mixed with the CTLs and then incubated at 37° C. for 4 hours. These cells were mixed so that the E/T ratio (cell number ratio) was 1:1, 5:1, 20:1 or 25:1, with the proviso that CTLs and the ⁵¹Cr-labeled target cells are expressed as “E” and “T”, respectively. After the completion of incubation, 100 μL of the supernatant was collected from each well. The amount of ⁵¹Cr release from the labeled cells was determined, and the specific lysis (%) based on the ⁵¹Cr release was calculated. The specific lysis (%) was calculated in the following manner. Specific lysis (%)=(release from a test sample−spontaneous release)/(maximum release−spontaneous release)×100

In the formula, the amount of spontaneous release refers to the amount of fluorescence of culture supernatant in the wells containing target cells only, and the maximum release refers to the amount of fluorescence of culture medium in which the target cells have been completely lysed by treatment with 1 mass % Triton X-100.

The target cells to be used were B-LCLs, K562 cells, JY cells, and KH88 cells, which will be described in detail below. KH88 cells are the same as KH88OF8 cells used in the following Example 9.

B-LCLs, which were established by EB virus-mediated transformation of peripheral blood B lymphocytes obtained from an HLA-A*0206-positive blood donor, do not express WT1.

K562 cells, which were established from a patient with chronic myelogenous leukemia in blastic crisis, are a WT1-expressing, non-HLA class I-expressing cell line. The present inventor was not able to obtain a WT1-expressing, HLA-A*0206-positive wild-type leukemia cell line. For this reason, 0206K562 cells, which were prepared by transformation of K562 cells with HLA-A*0206 genes, were also used. The FACS analysis using an anti-HLA-A2 antibody (cloneBB7.2; manufactured by BD Biosciences Pharmingen) showed that the 0206K562 cells transformed with HLA-A*0206 genes express HLA-A*0206 molecules on the cell surfaces.

The western blot analysis showed that B-LCL cells transformed with the WT1 gene express WT1. B-LCL cells transformed with a mock vector were used as a control.

JY cells are a non-WT1-expressing, HLA-A*0206-negative B cell line established by EB virus-mediated transformation.

KH88 cells are a WT1-expressing, HLA-A*0206-negative leukemia cell line.

Each cell line was cultured in a RPMI1640 culture medium supplemented with 10 v/v % heat-inactivated fetal bovine serum, 50 IU/mL penicillin and 50 mg/mL streptomycin.

(5) Antibody and Flow Cytometry Analysis

Anti-human CD14, CD86, CD80, CD83 and HLA-DR mAbs were purchased from BD. Concentration and maturation of DCs were confirmed by analysis of cell surface antigens using the monoclonal antibodies (mAbs) listed above. Samples were analyzed with a flow cytometer (FACS Calibur; manufactured by BD) using CellQest software.

(6) Results

It was examined whether WT1₁₈₇ peptide-specific CTLs can be prepared from PBMCs of HLA-A*0206-positive blood donors. The WT1₁₈₇ peptide-specific cytotoxic activity was examined using the CTLs obtained by repeatedly stimulating the CD8-positive T cell-enriched PBMCs from the HLA-A*0206-positive healthy blood donor with WT1₁₈₇ peptide-pulsed autologous DCs or PBMCs. The CTLs showed a stronger cytotoxic activity against WT1₁₈₇ peptide-pulsed autologous B-LCL cells than against non-WT1₁₈₇ peptide-pulsed B-LCL cells (FIG. 1 a). In FIG. 1 a, the vertical axis represents the cytotoxic activity, and the horizontal axis represents the ratio of CTLs obtained by peptide stimulation (effector: E) relative to target cells (target: T) (E/T ratio). The closed triangle represents the cells pulsed with 10 μg/mL of the WT1₁₈₇ peptide, and the closed square represents the cells not pulsed with the WT1₁₈₇ peptide. The same cytotoxic activity as above was shown also by the CTLs similarly prepared from the PBMCs isolated from the two different HLA-A*0206-positive healthy blood donors (FIGS. 2 a and 2 b). In FIG. 2, the closed triangle represents the cells pulsed with 10 μg/mL of the WT1₁₈₇ peptide, and the closed square represents the cells not pulsed with the WT1₁₈₇ peptide. These results show that each cytotoxic activity is specific to the WT1₁₈₇ pep tide.

The cytotoxic activity of the CTLs increased in parallel with the concentration of the WT1₁₈₇ peptide used to pulse the DCs or PBMCs with, and reached the plateau at the peptide concentration of 0.1 μg/mL (FIG. 1 b). The half maximum concentration of the WT1₁₈₇ peptide for specific lysis (half-maximal lysis value) was about 5×10⁻⁵ μg/mL. This shows that the affinity of TCRs (T cell antigen receptors) of the CTLs to a WT1₁₈₇ peptide/HLA-A*0206 complex was relatively high. This result strongly suggests that CTLs induced with the WT1₁₈₇ peptide can recognize the WT1₁₈₇ peptide.

In the same manner as above, the cytotoxic activity against various target cells endogenously expressing WT1 was examined using the CTLs obtained by stimulating the CD8-positive T cell-enriched PBMCs from the HLA-A*0206-positive blood donor with WT1₁₈₇ peptide-pulsed DCs or PBMCs. The results are shown in FIGS. 3 a and 3 b. The respective cytotoxic activities for the target cells shown in FIGS. 3 a and 3 b were determined at the same time. FIG. 3 a shows the cytotoxic activity of WT1₁₈₇ peptide-specific CTLs against B-LCLs transformed with the WT1 gene (WT1-expressing, HLA-A*0206-positive; closed triangle), or B-LCLs transformed with a mock vector (non-WT1-expressing, HLA-A*0206-positive; closed square). FIG. 3 b shows that the cytotoxic activity of WT1₁₈₇ peptide-specific CTLs against 0206K562 cells (WT1-expressing, HLA-A*0206-positive; closed square), K562 cells (WT1-expressing, HLA-A*0206-negative; open square), KH88 cells (WT1-expressing, HLA-A*0206-negative; closed circle), or JY cells (non-WT1-expressing, HLA-A*0206-negative; closed triangle).

The CTLs showed a stronger cytotoxic activity against the B-LCLs transformed with WT1 (WT1-expressing, HLA-A*0206-positive) than against the B-LCLs transformed with a mock vector (non-WT1-expressing, HLA-A*0206-positive) (FIG. 3 a). Further, as shown in FIG. 3 b, the CTLs showed a stronger cytotoxic activity against the 0206K562 cells transformed with HLA-A*0206 (WT1-expressing, HLA-A*0206-positive) than against the K562 cells (WT1-expressing, HLA-A*0206-negative), the KH88 cells (WT1-expressing, HLA-A*0206-negative), or the JY cells (non-WT1-expressing, HLA-A*0206-negative). In other words, the CTLs showed a significant cytotoxic activity against WT1-expressing, HLA-A*0206-positive target leukemia cells, but no cytotoxic activity against non-WT1-expressing and/or HLA-A*0206-negative cells. This result demonstrates that WT1₁₈₇ peptide-specific CTLs prepared in vitro show the cytotoxic activity against tumor cells endogenously expressing WT1 like leukemia cells and being HLA-A*0206-positive. The result in FIG. 3 b strongly suggests that the cytotoxic activity of WT1₁₈₇ peptide-specific CTLs was restricted by HLA-A class I. This is based on the fact that a stronger cytotoxic activity was observed against 0206K562 cells than against K562 cells.

The above results demonstrate that the above-mentioned cultured CTLs are WT1₁₈₇ peptide-specific CTLs.

The results of each figure are typical data, and basically reproducible with some variation.

Example 3 Confirmation of the HLA Class by Which WT1₁₈₇ Peptide-specific CTLs are Restricted

It was examined whether the cytotoxic activity of the WT1₁₈₇ peptide-specific CTLs obtained in Example 2 was restricted by HLA class I. The ⁵¹Cr release cytotoxicity test was performed in the presence or absence of mAbs against HLA class I or HLA class II. Autologous B-LCLs were used as a target cell. In this experiment, the E/T ratio was 5:1.

The results are shown in FIG. 4. FIG. 4 a shows the results of the test that was performed using B-LCLs (non-WT1₁₈₇-expressing, HLA-A*0206-positive) as a target cell in the absence of mAbs against HLA class I (anti-HLA class I mAbs) and mAbs against HLA class II (anti-HLA class II mAbs). FIG. 4 b shows the results of the test that was performed using WT1₁₈₇ peptide-pulsed B-LCLs (WT1₁₈₇-expressing, HLA-A*0206-positive) as a target cell in the absence of anti-HLA class I mAbs and in the presence of anti-HLA class II mAbs. FIG. 4 c shows the results of the test that was performed using WT1₁₈₇ peptide-pulsed B-LCLs (WT1₁₈₇-expressing, HLA-A*0206-positive) as a target cell in the presence of anti-HLA class I mAbs and in the absence of anti-HLA class II mAbs. FIG. 4 d shows the results of the test that was performed using WT1₁₈₇ peptide-pulsed B-LCLs (WT1₁₈₇-expressing, HLA-A*0206-positive) as a target cell in the absence of anti-HLA class I mAbs and anti-HLA class II mAbs.

As shown in FIG. 4, the cytotoxic activity of the WT1₁₈₇ peptide-specific CTLs was completely inhibited by addition of an anti-HLA class I antibody, not an anti-HLA class II antibody. The result shows that the cytotoxic activity of WT1₁₈₇ peptide-specific CTLs was restricted by HLA class I as expected.

Example 4 Cytotoxicity Test Against Tumor Cells

The cytotoxicity test against WT1-expressing, HLA-A*0206-positive tumor cells was performed in vitro using the WT1₁₈₇ peptide-specific CTLs obtained in Example 2. The cytotoxicity test was performed according to the ⁵¹Cr release cytotoxicity test described in Example 2. As a result, the WT1₁₈₇ peptide-specific CTLs showed the cytotoxic activity against WT1-expressing tumor cells (data not shown).

Example 5 Preparation of WT1₁₂₆ Peptide-specific CTLs, and Cytotoxicity Test of the CTLs

WT1₁₂₆ peptide-specific CTLs were prepared in the same manner as in Example 2 (3) except that the WT1₁₂₆ peptide (SEQ ID NO: 3) was used instead of the WT1₁₈₇ peptide. The cytotoxicity test was performed using these CTLs in the same manner as in Example 2, to determine the WT1₁₂₆ peptide-specific cytotoxic activity. FIG. 5 shows the cytotoxic activity of WT1₁₂₆ peptide-specific CTLs induced from PBMCs of the same HLA-A*0206-positive healthy blood donor as in FIG. 2 b. In FIG. 5, the closed triangle represents cells pulsed with 10 μg/mL of the WT1₁₂₆ peptide, and the closed square represents cells not pulsed with the WT1₁₂₆ peptide. The CTLs showed a stronger cytotoxic activity against the WT1₁₂₆ peptide-pulsed autologous B-LCL cells than against the non-WT1₁₂₆ peptide-pulsed B-LCL cells (FIG. 5). This result shows that the cytotoxic activity of the CTLs is specific to the WT1₁₂₆ peptide.

In the same manner as in Example 2, the cytotoxic activity against various target cells endogenously expressing WT1 was examined using the CTLs prepared by stimulating the CD8-positive T cell-enriched PBMCs from the HLA-A*0206-positive blood donors with WT1₁₂₆ peptide-pulsed DCs or PBMCs. The cytotoxic activity against each target cell is shown in FIGS. 6 a and 6 b. The target cells in FIGS. 6 a and 6 b are 0206K562 cells (WT1-expressing, HLA-A*0206-positive; closed square), K562 cells (WT1-expressing, HLA-A*0206-negative; open square), KH88 cells (WT1-expressing, HLA-A*0206-negative; closed circle), and JY cells (non-WT1-expressing, HLA-A*0206-negative; closed triangle). FIG. 6 a shows the cytotoxic activity of WT1₁₂₆ peptide-specific CTLs induced from PBMCs of the same HLA-A*0206-positive healthy blood donor as in FIG. 2 a. FIG. 6 b shows the cytotoxic activity of WT1₁₂₆ peptide-specific CTLs induced from PBMCs of the same HLA-A*0206-positive healthy blood donor as in FIG. 2 b.

Like WT1₁₈₇ peptide-specific CTLs, the WT1₁₂₆ peptide-specific CTLs showed a significant cytotoxic activity against WT1-expressing, HLA-A*0206-positive target leukemia cells, but no cytotoxic activity against non-WT1-expressing and/or HLA-A*0206-negative cells. This result demonstrates that WT1₁₂₆ peptide-specific CTLs prepared in vitro show the cytotoxic activity against tumor cells endogenously expressing WT1 like leukemia cells and being HLA-A*0206-positive. The results of FIGS. 6 a and 6 b strongly suggest that the cytotoxic activity of WT1₁₂₆ peptide-specific CTLs was restricted by HLA-A class I. This is based on the fact that a stronger cytotoxic activity was observed against 0206K562 cells than against K562 cells.

The above results demonstrate that the obtained CTLs are WT1₁₂₆ peptide-specific CTLs.

The results of each figure are typical data, and basically reproducible with some variation.

Example 6 Preparation of Vaccine Compositions

The following cancer vaccine compositions 1 to 8 were prepared. These are only examples of the cancer vaccine composition of the present invention.

Cancer Vaccine Composition 1

WT1₁₈₇ peptide  3 mg Montanide ISA-51 400 mg 5% glucose in water 400 mg

The above-mentioned ingredients were mixed and the mixture was named cancer vaccine composition 1.

Cancer Vaccine Composition 2

WT1₁₈₇ peptide  1 mg Montanide ISA-51 400 mg 5% glucose in water 400 mg

The above-mentioned ingredients were mixed and the mixture was named cancer vaccine composition 2.

Cancer Vaccine Composition 3

WT1₁₈₇ peptide 0.001 mg   Montanide ISA-51 400 mg 5% glucose in water 400 mg

The above-mentioned ingredients were mixed and the mixture was named cancer vaccine composition 3.

Cancer Vaccine Composition 4

WT1₁₈₇ peptide  10 mg Montanide ISA-51 400 mg 5% glucose in water 400 mg

The above-mentioned ingredients were mixed and the mixture was named cancer vaccine composition 4.

Cancer Vaccine Compositions 5 to 8

Cancer vaccine compositions 5 to 8 were prepared in the same manner as in the above-mentioned cancer vaccine compositions 1 to 4 except that the WT1₁₂₆ peptide was used instead of the WT1₁₈₇ peptide.

Example 7 Affinity of Modified Peptides to HLA-A*0206 Molecules

As for the WT1₁₈₇ peptide, the WT1₁₂₆ peptide, and modified peptides comprising substitution of an amino acid residue at position 1, 2, 3 or 9 from the N terminus of the WT1₁₈₇ peptide or the WT1₁₂₆ peptide, the affinity to HLA-A*0206 molecules was analyzed by use of the NetMHC2.0 Server-prediction program. The analysis results of modified WT1₁₈₇ peptides and modified WT1₁₂₆ peptides are shown in Tables 1 and 2, respectively. The smaller value (the peptide has a binding ability at a lower concentration) indicates the higher affinity.

TABLE 1 Amino acid SEQ ID Predicted Affinity Binding Peptide sequence NO score (nM) Strength WT1₁₈₇ SLGEQQYSV 2 0.776 11 Strong binding (SB) WT1₁₈₇P1G GLGEQQYSV 4 0.756 13 SB WT1₁₈₇P1A ALGEQQYSV 5 0.812 7 SB WT1₁₈₇P1V VLGEQQYSV 6 0.755 14 SB WT1₁₈₇P1L LLGEQQYSV 7 0.810 7 SB WT1₁₈₇P1I ILGEQQYSV 8 0.782 10 SB WT1₁₈₇P1M MLGEQQYSV 9 0.877 3 SB WT1₁₈₇P1W WLGEQQYSV 10 0.876 3 SB WT1₁₈₇P1F FLGEQQYSV 11 0.926 2 SB WT1₁₈₇P1Y YLGEQQYSV 12 0.896 3 SB WT1₁₈₇P2V SVGEQQYSV 13 0.722 20 SB WT1₁₈₇P2Q SQGEQQYSV 14 0.824 6 SB WT1₁₈₇P2I SIGEQQYSV 15 0.734 17 SB WT1₁₈₇P2M SMGEQQYSV 16 0.798 8 SB WT1₁₈₇P3L SLLEQQYSV 17 0.865 4 SB WT1₁₈₇P3A SLAEQQYSV 18 0.844 5 SB WT1₁₈₇P3V SLVEQQYSV 19 0.869 4 SB WT1₁₈₇P3M SLMEQQYSV 20 0.896 3 SB WT1₁₈₇P3P SLPEQQYSV 21 0.791 9 SB WT1₁₈₇P3W SLWEQQYSV 22 0.883 3 SB WT1₁₈₇P3F SLFEQQYSV 23 0.864 4 SB WT1₁₈₇P3Y SLYEQQYSV 24 0.857 4 SB WT1₁₈₇P3S SLSEQQYSV 25 0.801 8 SB WT1₁₈₇P3I SLIEQQYSV 26 0.880 3 SB WT1₁₈₇P9L SLGEQQYSL 53 0.586 88 weak binding

TABLE 2 Amino acid SEQ ID Predicted Affinity Binding Peptide sequence NO score (nM) Strength WT1₁₂₆ RMFPNAPYL 3 0.83 6 SB WT1₁₂₆P1G GMFPNAPYL 27 0.76 14 SB WT1₁₂₆P1A AMFPNAPYL 28 0.80 8 SB WT1₁₂₆P1V VMFPNAPYL 29 0.75 15 SB WT1₁₂₆P1L LMFPNAPYL 30 0.80 8 SB WT1₁₂₆P1I IMFPNAPYL 31 0.77 11 SB WT1₁₂₆P1M MMFPNAPYL 32 0.86 4 SB WT1₁₂₆P1W WMFPNAPYL 33 0.88 3 SB WT1₁₂₆P1F FMFPNAPYL 34 0.91 2 SB W71₁₂₆P1Y YMFPNAPYL 35 0.88 3 SB WT1₁₂₆P2V RVFPNAPYL 36 0.78 11 SB WT1₁₂₆P2Q RQFPNAPYL 37 0.85 4 SB WT1₁₂₆P2A RAFPNAPYL 38 0.67 35 SB WT1₁₂₆P2L RLFPNAPYL 39 0.80 8 SB WT1₁₂₆P2I RIFPNAPYL 40 0.78 10 SB WT1₁₂₆P3I RMIPNAPYL 41 0.84 5 SB WT1₁₂₆P3L RMLPNAPYL 42 0.83 6 SB WT1₁₂₆P3G RMGPNAPYL 43 0.71 23 SB WT1₁₂₆P3A RMAPNAPYL 44 0.79 9 SB WT1₁₂₆P3V RMVPNAPYL 45 0.82 6 SB WT1₁₂₆P3M RMMPNAPYL 46 0.86 4 SB WT1₁₂₆P3P RMPPNAPYL 47 0.72 21 SB WT1₁₂₆P3W RMWPNAPYL 48 0.85 5 SB WT1₁₂₆P9V RMFPNAPYV 49 0.91 2 SB WT1₁₂₆P9A RMFPNAPYA 50 0.77 12 SB WT1₁₂₆P9I RMFPNAPYI 51 0.81 7 SB WT1₁₂₆P9M RMFPNAPYM 52 0.65 42 SB

Example 8 Affinity of Modified Peptides to HLA-A*0201 Molecules

As for the WT1₁₈₇ peptide, the WT1₁₂₆ peptide, and modified peptides comprising substitution of an amino acid residue at position 1, 2, 3 or 9 from the N terminus of the WT1₁₈₇ peptide or the WT1₁₂₆ peptide, the affinity to HLA-A*0201 molecules was analyzed by use of the NetMHC2.0 Server-prediction program. The analysis results of modified WT1₁₈₇ peptides and modified WT1₁₂₆ peptides are shown in Tables 3 and 4, respectively. The smaller value indicates the higher affinity.

TABLE 3 Amino acid SEQ ID Predicted Affinity Binding Peptide sequence NO score (nM) Strength WT1₁₈₇ SLGEQQYSV 2 0.721 20 SB WT1₁₈₇P1G GLGEQQYSV 4 0.672 34 SB WT1₁₈₇P1A ALGEQQYSV 5 0.648 44 SB WT1₁₈₇P1V VLGEQQYSV 6 0.705 24 SB WT1₁₈₇P1L LLGEQQYSV 7 0.658 40 SB WT1₁₈₇P1I ILGEQQYSV 8 0.698 26 SB WT1₁₈₇P1M MLGEQQYSV 9 0.717 21 SB WT1₁₈₇P1W WLGEQQYSV 10 0.628 55 SB WT1₁₈₇P1F FLGEQQYSV 11 0.824 6 SB WT1₁₈₇P1Y YLGEQQYSV 12 0.809 7 SB WT1₁₈₇P2I SIGEQQYSV 15 0.556 121 SB WT1₁₈₇P2M SMGEQQYSV 16 0.740 16 SB WT1₁₈₇P3A SLAEQQYSV 18 0.811 7 SB WT1₁₈₇P3V SLVEQQYSV 19 0.766 12 SB WT1₁₈₇P3M SLMEQQYSV 20 0.876 3 SB WT1₁₈₇P3W SLWEQQYSV 22 0.863 4 SB WT1₁₈₇P3F SLFEQQYSV 23 0.852 4 SB WT1₁₈₇P3Y SLYEQQYSV 24 0.854 4 SB WT1₁₈₇P3S SLSEQQYSV 25 0.793 9 SB WT1₁₈₇P9L SLGEQQYSL 53 0.640 49 SB

TABLE 4 Amino acid SEQ ID Predicted Affinity Binding Peptide sequence NO score (nM) Strength WT1₁₂₆P1G GMFPNAPYL 27 0.80 9 SB WT1₁₂₆P1A AMFPNAPYL 28 0.81 7 SB WT1₁₂₆P1V VMFPNAPYL 29 0.81 8 SB WT1₁₂₆P1L LMFPNAPYL 30 0.82 7 SB WT1₁₂₆P1I IMFPNAPYL 31 0.81 8 SB WT1₁₂₆P1M MMFPNAPYL 32 0.85 4 SB WT1₁₂₆P1W WMFPNAPYL 33 0.80 8 SB WT1₁₂₆P1F FMFPNAPYL 34 0.91 2 SB WT1₁₂₆P1Y YMFPNAPYL 35 0.90 2 SB WT1₁₂₆P2V RVFPNAPYL 36 0.55 127 SB WT1₁₂₆P2Q RQFPNAPYL 37 0.49 262 SB WT1₁₂₆P2L RLFPNAPYL 39 0.78 10 SB WT1₁₂₆P2I RIFPNAPYL 40 0.64 48 SB WT1₁₂₆P3I RMIPNAPYL 41 0.74 16 SB WT1₁₂₆P3L RMLPNAPYL 42 0.78 10 SB WT1₁₂₆P3G RMGPNAPYL 43 0.60 73 SB WT1₁₂₆P3A RMAPNAPYL 44 0.73 17 SB WT1₁₂₆P3V RMVPNAPYL 45 0.68 31 SB WT1₁₂₆P3M RMMPNAPYL 46 0.83 6 SB WT1₁₂₆P3P RMPPNAPYL 47 0.61 66 SB WT1₁₂₆P3W RMWPNAPYL 48 0.83 6 SB WT1₁₂₆P9V RMFPNAPYV 49 0.84 5 SB WT1₁₂₆P9A RMFPNAPYA 50 0.73 18 SB WT1₁₂₆P9I RMFPNAPYI 51 0.79 9 SB WT1₁₂₆P9M RMFPNAPYM 52 0.69 29 SB

Example 9 Comparison of HLA-A*0201-restricted CTLs Induced by Various Modified WT1₁₂₆ Peptides

(1) Purpose

In view of the results of Example 8, the WT1₁₂₆P1F peptide (SEQ ID NO: 34), the WT1₁₂₆P2L peptide (SEQ ID NO: 39), the WT1₁₂₆P3M peptide (SEQ ID NO: 46) and the WT1₁₂₆P9V peptide (SEQ ID NO: 49) were selected as modified WT1₁₂₆ peptides to be tested, and the following experiments were conducted to screen for modified WT1₁₂₆ peptides capable of inducing CTLs having a high cytotoxic activity. The reagents, media, experimental methods, etc. used in Examples 9 to 12 were the same as in Example 1, unless otherwise specified. In Examples 9 to 12, culture was performed at 37° C., unless otherwise specified.

(2) Materials and Methods

From a healthy human donor showing expression of HLA-A*0201 molecules (HLA-A*0201-positive healthy blood donor), PBMCs were isolated, and CD14-positive cells were separated from the PBMCs by use of anti-human CD14 Magnetic Particles-DM. A culture medium was prepared by adding 800 IU/mL GM-CSF and 1000 IU/mL IL-4 to an X-VIVO15 medium supplemented with 1 v/v % human AB serum, and the CD14-positive cells were cultured in the culture medium for 1 day.

To the above culture, a maturation cytokine cocktail containing 10 ng/mL TNFα, 10 ng/mL IL-β, 1000 IU/mL IL-6 and 1 μg/mL PGE2 was added. After additional one day culture, autologous mature DCs were obtained.

The autologous mature DCs were pulsed with 10 μg/mL of a WT1₁₂₆ modified peptide obtained in Example 13 (the WT1₁₂₆P1F peptide, the WT1₁₂₆P2L peptide, the WT1₁₂₆P3M peptide or the WT1₁₂₆P9V peptide), cultured for 4 hours, and irradiated with 35Gy of radiation. The thus-obtained cells were used as stimulator cells for CTL induction.

The PBMCs (2×10⁶ cells/well) serving as responder cells and the above-mentioned DCs (2×10⁵ cells/well) were co-cultured in a 24-well plate. One week later, re-stimulation was given by addition of T2 cells which had been pulsed with the peptide and irradiated with 75Gy of radiation. Three days after re-stimulation, 20 IU/mL of IL-2 was added. The same re-stimulation was repeated another 3 times by addition of the peptide-pulsed, irradiated T2 cells, and then CD8-positive cells in the responder cells were enriched.

As for the CD8-positive T cells, the reactivity on an HLA-A*0201 tetramer bound to the WT1₁₂₆ peptide was analyzed by a flow cytometer, and the cytotoxic activity against various target cells was examined.

The target cells to be used were K562 cells, 0206K562 cells, JY cells, KH88OF8 cells, TF-1 cells and THP-1 cells, which are shown in Table 5. The features of these cells are shown in Table 5. A B-lymphoblastoid cell line (B-LCL) established by EB viral infection from the blood of an HLA-A*0201-positive donor was also used as a target cell.

TABLE 5 Target cell HLA-A*0201 HLA-A*0206 WT1 K562 negative negative expressed 0206K562 negative positive expressed JY positive negative not expressed KH88OF8 negative negative expressed TF-1 positive negative expressed THP-1 positive negative expressed (3) Results

FIG. 7 shows the results of flow cytometric analysis of PBMCs from the HLA-A*0201-positive donor 1 which were stimulated with different modified WT1₁₂₆ peptides and then stained with a PE (Phycoerythrin)-labeled HLA-A*0201 tetramer bound to the WT1₁₂₆ peptide (Medical & Biological Laboratories, Co., Ltd.), and an APC-Cy7-labeled anti-CD8 antibody (APC-Cy7: Allophycocyanin-Cyanine-7). When the PBMCs are stained with the above-mentioned tetramer and anti-CD8 antibody, CTLs induced by stimulation with the modified peptide bind to the tetramer and the anti-CD8 antibody, and thereby, fluorescence emitted by the tetramer and fluorescence emitted by the anti-CD8 antibody can be detected, respectively. In FIGS. 7 a to 7 e, the vertical axis represents the intensity of fluorescence emitted by the HLA-A*0201 tetramer, and the horizontal axis represents the intensity of fluorescence emitted by the anti-CD8 antibody. Each box in FIGS. 7 a to 7 e shows the frequency (%) of induced, HLA-A*0201-restricted CTLs capable of recognizing the WT1₁₂₆ peptide. FIG. 7 a shows the analysis result of PBMCs which were not stimulated with any WT1₁₂₆ modified peptide and stained with the above-mentioned tetramer and anti-CD8 antibody (background). FIG. 7 b shows the analysis result of PBMCs which were stimulated with the WT1₁₂₆P1F peptide and stained. FIG. 7 c shows the analysis result of PBMCs which were stimulated with the WT1₁₂₆P2L peptide and stained. FIG. 7 d shows the analysis result of PBMCs which were stimulated with the WT1₁₂₆P3M peptide and stained. FIG. 7 e shows the analysis result of PBMCs which were stimulated with the WT1₁₂₆P9V peptide and stained.

The frequency of the above-mentioned CTLs induced by stimulation of PBMCs with the WT1₁₂₆P1F peptide was 0.14% (FIG. 7 b). The frequency of the above-mentioned CTLs induced by stimulation of PBMCs with the WT1₁₂₆P2L peptide was 0.37% (FIG. 7 c). The CTLs induced separately with these peptides were HLA tetramer-positive, CD8-positive and capable of binding to the HLA-A*0201 tetramer bound to the WT1₁₂₆ peptide. These results show that stimulation of PBMCs with the modified WT1₁₂₆ peptide induced CTLs which can recognize the wild-type peptide (WT1₁₂₆ peptide).

FIG. 8 shows the measurement results of the cytotoxic activity of CTLs induced by stimulation of PBMCs from the donor 1 with the WT1₁₂₆P1F peptide. In FIG. 8, the vertical axis represents the cytotoxic activity, and the horizontal axis represents the ratio of CD8-positive T cells obtained by peptide stimulation (effector: E) relative to target cells (target: T) (E/T ratio). The closed diamond represents the group in which JY cells were used as a target cell, and the closed square represents the group in which JY cells pulsed with the WT1₁₂₆P1F peptide were used as a target cell.

JY cells are HLA-A*0201-positive and WT1-negative. The CTLs showed a stronger cytotoxic activity against the WT1₁₂₆P1F peptide-pulsed JY cells than against the non-WT1₁₂₆P1F peptide-pulsed JY cells. This result shows that CTLs which are specific to the peptide used for the above-mentioned stimulation and restricted by HLA-A*0201 were induced.

FIG. 9 shows the measurement results of the cytotoxic activity of CTLs induced by stimulation of PBMCs from the donor 1 with the WT1₁₂₆P2L peptide. In FIG. 9, the vertical axis represents the cytotoxic activity, and the horizontal axis represents the ratio of CD8-positive T cells obtained by peptide stimulation (effector: E) relative to target cells (target: T) (E/T ratio). In FIG. 9 a, the closed diamond represents the group in which JY cells were used as a target cell, and the closed square represents the group in which JY cells pulsed with the WT1₁₂₆P2L peptide were used as a target cell. In FIG. 9 b, the closed diamond represents the group in which TF-1 cells were used as a target cell, the closed square represents the group in which THP-1 cells were used as a target cell, the closed triangle represents the group in which KH88OF8 cells were used as a target cell, and the cross represents the group in which B-LCL cells were used as a target cell.

The induced CTLs showed a stronger cytotoxic activity against the WT1₁₂₆P2L peptide-pulsed JY cells than against the non-WT1₁₂₆P2L peptide-pulsed JY cells (FIG. 9 a). The induced CTLs showed a stronger cytotoxic activity against the TF-1 cells and THP-1 cells, both of which are HLA-A*0201-positive and WT1-positive, than against the KH88OF8 cells, which are HLA-A*0201-negative and WT1-positive, and the B-LCL cells, which are HLA-A*0201-positive and WT1-negative (FIG. 9 b). As is clear from the results, the CTLs induced by stimulation with the WT1₁₂₆P2L peptide are restricted by HLA-A*0201, and capable of destroying cancer cells endogenously expressing WT1.

FIG. 10 shows the results of flow cytometric analysis of PBMCs from the HLA-A*0201-positive donor 2 which were stimulated with the WT1₁₂₆P2L peptide and then stained with the PE-labeled HLA-A*0201 tetramer bound to the WT1₁₂₆ peptide, and the APC-Cy7-labeled anti-CD8 antibody. Namely, FIG. 10 shows the results of the flow cytometric analysis of induced CTLs which were stained with the HLA tetramer bound to the WT1₁₂₆ peptide, and the anti-CD8 antibody. The vertical axis represents the intensity of fluorescence emitted by the HLA-A*0201 tetramer, and the horizontal axis represents the intensity of fluorescence emitted by the anti-CD8 antibody.

The cells in the upper right area of FIG. 10 are induced CTLs which are restricted by HLA-A*0201 and can recognize the WT1₁₂₆ peptide. 5.43% of lymphocytes of the PBMCs stimulated with the WT1₁₂₆P2L peptide were HLA tetramer-positive, CD8-positive CTLs which are capable of binding to the tetramer of HLA-A*0201 bound to the WT1₁₂₆ peptide. This result shows that stimulation of PBMCs with the modified peptide induced CD8-positive CTLs which can recognize the wild-type peptide.

FIG. 11 shows the measurement results of the cytotoxic activity of the CTLs induced by stimulation of PBMCs from the donor 2 with the WT1₁₂₆P2L peptide. In FIGS. 11 a and 11 b, the vertical axis represents the cytotoxic activity, and the horizontal axis represents the ratio of CD8-positive T cells obtained by peptide stimulation (effector: E) relative to target cells (target: T) (E/T ratio). In FIG. 11 a, the closed diamond represents the group in which JY cells were used as a target cell, and the closed square represents the group in which cell. In FIG. 11 b, the closed diamond represents the group in which JY cells were used as a target cell, and the closed square represents the group in which JY cells pulsed with the WT1₁₂₆P2L peptide were used as a target cell.

The induced CTLs showed a stronger cytotoxic activity against the WT1₁₂₆ peptide-pulsed JY cells than against the non-WT1₁₂₆ peptide-pulsed JY cells (FIG. 11 a). The induced CTLs also showed a stronger cytotoxic activity against the WT1₁₂₆P2L peptide-pulsed JY cells than against the non-WT1₁₂₆P2L peptide-pulsed JY cells (FIG. 11 b). As is clear from the results, the CTLs induced by stimulation with the WT1₁₂₆P2L peptide can recognize both of the WT1₁₂₆P2L peptide and the wild-type WT1₁₂₆ peptide.

Example 10 Comparison of HLA-A*0206-restricted CTLs Induced by Various Modified WT1₁₂₆ Peptides

(1) Purpose

In view of the results of Example 7, the WT1₁₂₆P1F peptide, the WT1₁₂₆P2L peptide, the WT1₁₂₆P3M peptide and the WT1₁₂₆P9V peptide were selected as modified WT1₁₂₆ peptides to be tested, and the following experiments were conducted to screen for modified WT1₁₂₆ peptides capable of inducing CTLs having a high cytotoxic activity.

(2) Materials and Methods

From a healthy human donor showing expression of HLA-A*0206 molecules (HLA-A*0206-positive healthy blood donor), PBMCs were isolated, and CD14-positive cells were separated from the PBMCs by use of anti-human CD14 Magnetic Particles-DM. A culture medium was prepared by adding 800 IU/mL GM-CSF and 1000 IU/mL IL-4 to an X-VIVO15 medium supplemented with 1 v/v % human AB serum, and the CD14-positive cells were cultured in the culture medium for 1 day.

To the above culture, a maturation cytokine cocktail containing 10 ng/mL TNFα, 10 ng/mL IL-β, 1000 IU/mL IL-6 and 1 μg/mL PGE2 was added. After additional one day culture, autologous mature DCs were obtained.

The autologous mature DCs were pulsed with 10 μg/mL of a WT1₁₂₆ modified peptide obtained in Example 13 (the WT1₁₂₆P1F peptide, the WT1₁₂₆P2L peptide, the WT1₁₂₆P3M peptide or the WT1₁₂₆P9V peptide), cultured for 4 hours, and irradiated with 35Gy of radiation. The thus-obtained cells were used as stimulator cells for CTL induction.

CD8-positive T cell-enriched PBMCs (2×10⁶ cells/well) and the above-mentioned DCs (1×10⁵ cells/well) were co-cultured in a 24-well plate. Ten days later, re-stimulation was given by addition of PBMCs which had been pulsed with the peptide and irradiated with 35Gy of radiation. Two days after re-stimulation, 10 IU/mL of IL-2 and 10 ng/mL of IL-7 were added. After the same re-stimulation was repeated another 4 times, CD8-positive T cells were enriched. The CD8-positive T cells were examined for the cytotoxic activity against various target cells.

The target cells to be used were B-LCLs established by EB viral infection from the blood of an HLA-A*0206-positive donor, K562 cells and 0206K562 cells.

(3) Results

FIG. 12 shows the measurement results of the cytotoxic activity of CTLs induced by stimulation of PBMCs from the HLA-A*0206-positive donor 3 with different peptides. FIG. 12 a shows the cytotoxic activity of CTLs induced by stimulation with the WT1₁₂₆P2L peptide. FIG. 12 b shows the cytotoxic activity of CTLs induced by stimulation with the WT1₁₂₆P3M peptide. FIG. 12 c shows the cytotoxic activity of CTLs induced by stimulation with the WT1₁₂₆P9V peptide. In FIGS. 12 a to 12 c, the vertical axis represents the cytotoxic activity, and the horizontal axis represents the ratio of CD8-positive T cells obtained by peptide stimulation (effector: E) relative to target cells (target: T) (E/T ratio). The closed diamond represents the group in which autologous B-LCL cells were used as a target cell, and the closed square represents the group in which autologous B-LCL cells pulsed with the same modified WT1₁₂₆ peptide as used for the above-mentioned stimulation were used as a target cell.

The CTLs induced by stimulation with the WT1₁₂₆P2L peptide showed a stronger cytotoxic activity against the WT1₁₂₆P2L peptide-pulsed autologous B-LCL cells, which are HLA-A*0206-positive and WT1-negative, than against the non-WT1₁₂₆P2L peptide-pulsed autologous B-LCL cells (FIG. 12 a). The CTLs induced by stimulation with the WT1₁₂₆P3M peptide showed a stronger cytotoxic activity against the WT1₁₂₆P3M peptide-pulsed autologous B-LCL cells, which are HLA-A*0206-positive and WT1-negative, than against the non-WT1₁₂₆P3M peptide-pulsed autologous B-LCL cells (FIG. 12 b). The CTLs induced by stimulation with the WT1₁₂₆P9V peptide showed a stronger cytotoxic activity against the WT1₁₂₆P9V peptide-pulsed autologous B-LCL cells, which are HLA-A*0206-positive and WT1-negative, than against the non-WT1₁₂₆P9V peptide-pulsed autologous B-LCL cells (FIG. 12 c).

These results show that CTLs which are specific to the peptide used for the above-mentioned stimulation and restricted by HLA-A*0206 were induced.

FIG. 13 shows the measurement results of the cytotoxic activity of CTLs induced by stimulation of PBMCs from the HLA-A*0206-positive donor 3 with the WT1₁₂₆P9V peptide. In FIG. 13, the vertical axis represents the cytotoxic activity, and the horizontal axis represents the ratio of CD8-positive T cells obtained by peptide stimulation (effector: E) relative to target cells (target: T) (E/T ratio). The closed diamond represents the group in which autologous B-LCL cells were used as a target cell, and the closed square represents the group in which WT1 gene-transfected autologous B-LCL cells were used as a target cell.

In FIG. 13, the CTLs induced by stimulation with the WT1₁₂₆P9V peptide showed a stronger cytotoxic activity against autologous B-LCL cells made to be WT1-positive by transfection of the WT1 gene into B-LCL cells, which were originally HLA-A*0206-positive and WT1-negative, than against the non-WT1 gene-transfected autologous B-LCL cells (FIG. 12 c). As is clear from the result, the CTLs induced by stimulation with the WT1₁₂₆P9V peptide are restricted by HLA-A*0206, and show the cytotoxic activity by recognizing the wild-type WT1₁₂₆ peptide presented endogenously.

FIG. 14 shows the measurement results of the cytotoxic activity of CTLs induced by stimulation of PBMCs from the HLA-A*0206-positive donor 4 with different peptides. FIG. 14 a shows the cytotoxic activity of CTLs induced by stimulation with the WT1₁₂₆P2L peptide. FIG. 14 b shows the cytotoxic activity of CTLs induced by stimulation with the WT1₁₂₆P3M peptide. FIG. 14 c shows the cytotoxic activity of CTLs induced by stimulation with the WT1₁₂₆P9V peptide. In FIGS. 14 a to 14 c, the vertical axis represents the cytotoxic activity, and the horizontal axis represents the ratio of CD8-positive T cells obtained by peptide stimulation (effector: E) relative to target cells (target: T) (E/T ratio). The closed diamond represents the group in which autologous B-LCL cells were used as a target cell, and the closed square represents the group in which autologous B-LCL cells pulsed with the same modified WT1₁₂₆ peptide as used for the above-mentioned stimulation were used as a target cell.

The CTLs induced by stimulation with the WT1₁₂₆P2L peptide showed a stronger cytotoxic activity against the WT1₁₂₆P2L peptide-pulsed autologous B-LCL cells, which are HLA-A*0206-positive and WT1-negative, than against the non-WT1₁₂₆P2L peptide-pulsed autologous B-LCL cells (FIG. 14 a). The CTLs induced by stimulation with the WT1₁₂₆P3M peptide showed a stronger cytotoxic activity against the WT1₁₂₆P3M peptide-pulsed autologous B-LCL cells, which are HLA-A*0206-positive and WT1-negative, than against the non-WT1₁₂₆P3M peptide-pulsed autologous B-LCL cells (FIG. 14 b). The CTLs induced by stimulation with the WT1₁₂₆P9V peptide showed a stronger cytotoxic activity against the WT1₁₂₆P9V peptide-pulsed autologous B-LCL cells, which are HLA-A*0206-positive and WT1-negative, than against the non-WT1₁₂₆P9V peptide-pulsed autologous B-LCL cells (FIG. 14 c). These results show that CTLs which are specific to the peptide used for the above-mentioned stimulation and restricted by HLA-A*0206 were induced.

FIG. 15 shows the measurement results of the cytotoxic activity of CTLs induced by stimulation of PBMCs from the HLA-A*0206-positive donor 4 with different peptides. The target cells to be used were HLA-A*0206-negative, WT1-positive K562 cells, and K562 cells made to endogenously present WT1 antigen peptides by transfection of the HLA-A*0206 gene thereinto (0206K562 cells). FIG. 15 a shows the cytotoxic activity of CTLs induced by stimulation with the WT1₁₂₆P2L peptide. FIG. 15 b shows the cytotoxic activity of CTLs induced by stimulation with the WT1₁₂₆P3M peptide. FIG. 15 c shows the cytotoxic activity of CTLs induced by stimulation with the WT1₁₂₆P9V peptide. In FIGS. 15 a to 15 c, the vertical axis represents the cytotoxic activity, and the horizontal axis represents the ratio of CD8-positive T cells obtained by peptide stimulation (effector: E) relative to target cells (target: T) (E/T ratio). The closed diamond represents the group in which K562 cells were used as a target cell, and the closed square represents the group in which 0206K562 cells, i.e., K562 cells made to endogenously present WT1 antigen peptides by transfection of the HLA-A*0206 gene thereinto, were used as a target cell.

In FIGS. 15 a to 15 c, the CTLs induced by stimulation with the WT1₁₂₆P2L peptide, the WT1₁₂₆P3M peptide or the WT1₁₂₆P9V peptide showed a stronger cytotoxic activity against the 0206K562 cells than against the K562 cells, in each case. As is clear from the results, the CTLs induced by stimulation with any of these modified peptides are restricted by HLA-A*0206, and show the cytotoxic activity by recognizing the wild-type WT1₁₂₆ peptide presented endogenously.

Example 11 Comparison of HLA-A*0201-restricted CTLs Induced by Various Modified WT1₁₈₇ Peptides

(1) Purpose

In view of the results of Example 8, the WT1₁₈₇P1F peptide (SEQ ID NO: 11), the WT1₁₈₇P2M peptide (SEQ ID NO: 16) and the WT1₁₈₇P3M peptide (SEQ ID NO: 20) were selected as modified WT1₁₈₇ peptides to be tested, and the following experiments were conducted to screen for modified WT1₁₈₇ peptides capable of inducing CTLs having a high cytotoxic activity.

(2) Materials and Methods

From a healthy human donor showing expression of HLA-A*0201 molecules (HLA-A*0201-positive healthy blood donor), PBMCs were isolated, and CD14-positive cells were separated from the PBMCs using anti-human CD14 Magnetic Particles-DM. A culture medium was prepared by adding 800 IU/mL GM-CSF and 1000 IU/mL IL-4 to an X-VIVO15 medium supplemented with 1 v/v % human AB serum, and the CD14-positive cells were cultured in the culture medium for 1 day.

To the above culture, a maturation cytokine cocktail containing 10 ng/mL TNFα, 10 ng/mL IL-β, 1000 IU/mL IL-6 and 1 μg/mL PGE2 was added. After additional one day culture, autologous mature DCs were obtained.

The autologous mature DCs were pulsed with 10 μg/mL of a modified WT1₁₈₇ peptide obtained in Example 13 (the WT1₁₈₇P1F peptide, the WT1₁₈₇P2M peptide or the WT1₁₈₇P3M peptide), cultured for 4 hours, and irradiated with 35Gy of radiation. The thus-obtained cells were used as stimulator cells for CTL induction.

The PBMCs (2×10⁶ cells/well) serving as responder cells and the above-mentioned DCs (2×10⁵ cells/well) were co-cultured in a 24-well plate. One week later, re-stimulation was given by addition of T2 cells which had been pulsed with the peptide and irradiated with 75Gy of radiation. Three days after re-stimulation, 20 IU/mL of IL-2 was added. The same re-stimulation was repeated another 3 times by addition of the peptide-pulsed, irradiated T2 cells, and then CD8-positive cells in the responder cells were enriched. The CD8-positive T cells were examined for the cytotoxic activity against target cells, i.e., JY cells here.

(3) Results

FIG. 16 shows the measurement results of the cytotoxic activity of CTLs induced by stimulation of PBMCs from the HLA-A*0201-positive donor with the WT1₁₈₇P1F peptide (FIG. 16 a) or the WT1₁₈₇P2M peptide (FIG. 16 b). In FIGS. 16 a and 16 b, the vertical axis represents the cytotoxic activity, and the horizontal axis represents the ratio of CD8-positive T cells obtained by peptide stimulation (effector: E) relative to target cells (target: T) (E/T ratio). The closed diamond represents the group in which JY cells were used as a target cell, the closed triangle represents the group in which WT1₁₈₇ peptide-pulsed JY cells were used as a target cell, and the closed square represents the group in which JY cells pulsed with the WT1₁₈₇ modified peptide (WT1₁₈₇P1F peptide) that was used for the above-mentioned stimulation were used as a target cell. JY cells are HLA-A*0201-positive and WT1-negative.

The CTLs induced by stimulation with the WT1₁₈₇P1F peptide showed an equal cytotoxic activity against the WT1₁₈₇ peptide-pulsed JY cells and the WT1₁₈₇P1F peptide-pulsed JY cells, and the activity was stronger than that against the non-peptide-pulsed JY cells (FIG. 16 a). The CTLs induced by stimulation with the WT1₁₈₇P2M peptide showed an equal cytotoxic activity against the WT1₁₈₇ peptide-pulsed JY cells and the WT1₁₈₇P2M peptide-pulsed JY cells, and the activity was stronger than that against the non-peptide-pulsed JY cells (FIG. 16 b). As is clear from the results, the CTLs induced by stimulation with the modified peptide can recognize both of the modified peptide and the wild-type WT1₁₈₇ peptide.

Example 12 Comparison Of HLA-A*0206-restricted CTLs Induced by Various Modified WT1₁₈₇ Peptides)

(1) Purpose

In view of the results of Example 7, the WT1₁₈₇P1F peptide, the WT1₁₈₇P2M peptide and the WT1₁₈₇P3M peptide were selected as modified WT1₁₈₇ peptides to be tested, and the following experiments were conducted to screen for modified WT1₁₈₇ peptides capable of inducing CTLs having a high cytotoxic activity.

(2) Materials and Methods

From a healthy human donor showing expression of HLA-A*0206 molecules (HLA-A*0206-positive healthy blood donor), PBMCs were isolated, and CD14-positive cells were separated from the PBMCs using anti-human CD14 Magnetic Particles-DM. A culture medium was prepared by adding 800 IU/mL GM-CSF and 1000 IU/mL IL-4 to an X-VIVO15 medium supplemented with 1 v/v % human AB serum, and the CD14-positive cells were cultured in the culture medium for 1 day.

To the above culture, a maturation cytokine cocktail containing 10 ng/mL TNFα, 10 ng/mL IL-β, 1000 IU/mL IL-6 and 1 μg/mL PGE2 was added. After additional one day culture, autologous mature DCs were obtained.

The autologous mature DCs were pulsed with a modified WT1₁₈₇ peptide obtained in Example 13 (the WT1₁₈₇P1F peptide, the WT1₁₈₇P2M peptide or the WT1₁₈₇P3M peptide), cultured for 4 hours, and irradiated with 35Gy of radiation. The thus-obtained cells were used as stimulator cells for CTL induction.

CD8-positive T cell-enriched PBMCs (2×10⁶ cells/well) and the above-mentioned DCs (1×10⁵ cells/well) were co-cultured in a 24-well plate. Ten days later, re-stimulation was given by addition of PBMCs which had been pulsed with the peptide and irradiated with 35Gy of radiation. Two days after re-stimulation, 10 IU/mL of IL-2 and 10 ng/mL of IL-7 were added. After the same re-stimulation was repeated another 4 times, CD8-positive T cells were enriched. The CD8-positive T cells were examined for the cytotoxic activity against various target cells.

The target cells to be used were B-LCLs established by EB viral infection from the blood of an HLA-A*0206-positive donor, K562 cells and 0206K562 cells.

(3) Results

FIG. 17 shows the measurement results of the cytotoxic activity of CTLs induced by stimulation of PBMCs from the HLA-A*0206-positive donor with the WT1₁₈₇P1F peptide. In FIG. 17, the vertical axis represents the cytotoxic activity, and the horizontal axis represents the ratio of CD8-positive T cells obtained by peptide stimulation (effector: E) relative to target cells (target: T) (E/T ratio). In FIG. 17 a, the closed diamond represents the group in which B-LCL cells were used as a target cell, the closed square represents the group in which WT1₁₈₇ peptide-pulsed B-LCL cells were used as a target cell, and the closed triangle represents the group in which WT1₁₈₇P1F peptide-pulsed B-LCL cells were used as a target cell. In FIG. 17 b, the closed diamond represents the group in which K562 cells were used as a target cell, and the closed square represents the group in which 0206K562 cells, i.e., K562 cells made to endogenously present WT1 antigen peptides by transfection of the HLA-A*0206 gene thereinto, were used as a target cell.

The CTLs induced by stimulation with the WT1₁₈₇P1F peptide showed an equal cytotoxic activity against the WT1₁₈₇ peptide-pulsed B-LCL cells and the WT1₁₈₇P1F peptide-pulsed B-LCL cells, and the activity was stronger than that against the non-peptide-pulsed B-LCL cells (FIG. 17 a). When HLA-A*0206-negative, WT1-positive K562 cells, and K562 cells made to endogenously present WT1 antigen peptides by transfection of the HLA-A*0206 gene thereinto (0206K562 cells) were used as a target cell, the CTLs induced by stimulation with the WT1₁₈₇P1F peptide showed a stronger cytotoxic activity against the 0206K562 cells than against the K562 cells (FIG. 17 b). As is clear from the results, the CTLs induced by stimulation with the WT1₁₈₇P1F peptide can recognize both of the WT1₁₈₇P1F peptide and the wild-type WT1₁₈₇ peptide. Similarly, it was found that the CTLs are restricted by HLA-A*0206, and show the cytotoxic activity by recognizing the wild-type WT1₁₈₇ peptide presented endogenously.

FIG. 18 shows the measurement results of the cytotoxic activity of CTLs induced by stimulation of PBMCs from the HLA-A*0206-positive donor with the WT1₁₈₇P2M peptide. In FIG. 18, the vertical axis represents the cytotoxic activity, and the horizontal axis represents the ratio of CD8-positive T cells obtained by peptide stimulation (effector: E) relative to target cells (target: T) (E/T ratio). In FIG. 18 a, the closed diamond represents the group in which B-LCL cells were used as a target cell, the closed square represents the group in which WT1₁₈₇ peptide-pulsed B-LCL cells were used as a target cell, and the closed triangle represents the group in which WT1₁₈₇P2M peptide-pulsed B-LCL cells were used as a target cell. In FIG. 18 b, the closed diamond represents the group in which K562 cells were used as a target cell, and the closed square represents the group in which 0206K562 cells, i.e., K562 cells made to endogenously present WT1 antigen peptides by transfection of the HLA-A*0206 gene thereinto, were used as a target cell.

The CTLs induced by stimulation with the WT1₁₈₇P2M peptide showed an equal cytotoxic activity against the WT1₁₈₇ peptide-pulsed B-LCL cells and the WT1₁₈₇P2M peptide-pulsed B-LCL cells, and the activity was stronger than that against the non-peptide-pulsed B-LCL cells (FIG. 18 a). When HLA-A*0206-negative, WT1-positive K562 cells, and K562 cells made to endogenously present WT1 antigen peptides by transfection of the HLA-A*0206 gene thereinto (0206K562 cells) were used as a target cell, the CTLs induced by stimulation with the WT1₁₈₇P2M peptide showed a stronger cytotoxic activity against the 0206K562 cells than against the K562 cells (FIG. 18 b). As is clear from the results, the CTLs induced by stimulation with the WT1₁₈₇P2M peptide can recognize both of the WT1₁₈₇P2M peptide and the wild-type WT1₁₈₇ peptide. Similarly, it was found that the CTLs are restricted by HLA-A*0206, and show the cytotoxic activity by recognizing the wild-type WT1₁₈₇ peptide presented endogenously.

As is clear from the results of Examples 9 to 12, the CTLs induced by stimulation with the modified WT1₁₂₆ peptide, i.e., the WT1₁₂₆P1F peptide, the WT1₁₂₆P2L peptide, the WT1₁₂₆P3M peptide or the WT1₁₂₆P9V peptide, are restricted by HLA-A*0206, and show the cytotoxic activity by recognizing the wild-type WT1₁₂₆ peptide presented endogenously. Inter alia, the WT1₁₂₆P9V peptide, the WT1₁₂₆P2L peptide and the WT1₁₂₆P3M peptide were highly effective.

As is clear from the above results, the CTLs induced by stimulation with the modified WT1₁₈₇ peptide, i.e., the WT1₁₈₇P1F peptide, the WT1₁₈₇P2M peptide or the WT1₁₈₇P3M peptide, are restricted by HLA-A*0206, and show the cytotoxic activity by recognizing the wild-type WT1₁₈₇ peptide presented endogenously. Inter alia, the WT1₁₈₇P2M peptide and the WT1₁₈₇P1F peptide were highly effective.

Therefore, it was shown that these modified peptides are effective in treatment and prevention of cancers accompanied by increased expression of the WT1 gene in HLA-A*0206-positive persons.

As is clear from the above results, the CTLs induced by stimulation with the modified WT1₁₂₆ peptide, i.e., the WT1₁₂₆P1F peptide, the WT1₁₂₆P2L peptide, the WT1₁₂₆P3M peptide or the WT1₁₂₆P9V peptide, are restricted by HLA-A*0201, and show the cytotoxic activity by recognizing the wild-type WT1₁₂₆ peptide presented endogenously. Inter alia, the WT1₁₂₆P1F peptide and the WT1₁₂₆P2L peptide were highly effective.

As is clear from the above results, the CTLs induced by stimulation with the modified WT1₁₈₇ peptide, i.e., the WT1₁₈₇P1F peptide, the WT1₁₈₇P2M peptide or the WT1₁₈₇P3M peptide, are restricted by HLA-A*0201, and show the cytotoxic activity by recognizing the wild-type WT1₁₈₇ peptide presented endogenously. Inter alia, the WT1₁₈₇P2M peptide and the WT1₁₈₇P1F peptide were highly effective. Therefore, it was shown that these modified peptides are effective in treatment and prevention of cancers accompanied by increased expression of the WT1 gene in HLA-A*0201-positive persons.

Example 13 Synthesis of WT1₁₈₇P2V Peptide (SVGEQQYSV; SEQ ID NO: 13; H-Ser-Val-Gly-Glu-Gln-Gln-Tyr-Ser-Val-OH) (SEQ ID NO: 13))

1. Synthesis of Protected Peptide Resin (H-Ser(tBu)-Val-Gly-Glu(OtBu)-Gln(Trt)-Gln(Trt)-Tyr(tBu)-Ser(tBu)-Val-Alko-Resin (SEQ ID NO: 79))

0.4 g of an Fmoc-Val-Alko-resin (Alko is p-alkoxybenzyl alcohol) (manufactured by WATANABE CHEMICAL INDUSTRIES, LTD; 0.80 mmol/g) was placed into the reaction vessel of the ACT496 solid-phase synthesizer manufactured by Advanced ChemTech, washed with DMF(N,N′-dimethylformamide) (Step 1), treated with a 25% solution of piperidine in DMF (5 minutes×1 time, and 30 minutes×1 time) to remove the Fmoc group (Step 2), and was again washed with DMF (Step 3) to give an H-Val-Alko-resin. To this reaction vessel, 0.7 mL of NMP (N-methylpyrrolidinone) and a solution of 121 mg (0.96 mmol) of DIPCI (N,N′-diisopropylcarbodiimide) in 0.9 mL of NMP, and then a solution of 368 mg (0.96 mmol) of Fmoc-Ser(tBu)-OH and 147 mg (0.96 mmol) of HOBT (1-hydroxybenzotriazol) monohydrate in 1.8 mL of NMP were added. Coupling reaction was performed at room temperature for 60 minutes (Step 4). Additional coupling reaction was performed using the same amounts of Fmoc-Ser(tBu)-OH, HOBT monohydrate and DIPCI as above (Step 5). The resulting resin was washed with DMF (Step 6), deprotected (Step 7) and washed again (Step 8) to give an H-Ser(tBu)-Val-Alko-resin. Then, couplings were successively performed by repeating Steps 4 to 8 using Fmoc-Tyr(tBu)-OH, Fmoc-Gln(Trt)-OH, Fmoc-Gln(Trt)-OH, Fmoc-Glu(OtBu)-OH, Fmoc-Gly-OH, Fmoc-Val-OH and Fmoc-Ser(tBu)-OH. The resulting peptide resin was collected from the reaction vessel, washed with ether and then dried in vacuo to give 980 mg of an H-Ser(tBu)-Val-Gly-Glu(OtBu)-Gln(Trt)-Gln(Trt)-Tyr(tBu)-Ser (tBu)-Val-Alko-resin (SEQ ID NO: 79). The outline of the synthesis process mentioned above is shown in Table 6.

<Synthesis Process>

TABLE 6 Repetition Duration Step Reagent (time) (min) 1) washing DMF 3 mL 5 0.3 2) deprotection 25% piperidine/DMF 3 mL 1 5 1 30 3) washing DMF 3 mL 5 0.3 4) coupling Each Fmoc-amino acid (3 Eq), 1 60 HOBT(3 Eq), DIPCI(3 Eq)/NMP 3.4 mL 5) coupling Each Fmoc-amino acid (3 Eq), 1 60 HOBT(3 Eq), DIPCI(3 Eq)/NMP 3.4 mL 6) washing DMF 3 mL 5 0.3 7) deprotection 25% piperidine/DMF 3 mL 1 5 1 30 8) washing DMF 3 mL 5 0.3 2. Deprotection of Protected Peptide Resin

To 980 mg of the H-Ser(tBu)-Val-Gly-Glu(OtBu)-Gln(Trt)-Gln(Trt)-Tyr(tBu)-Ser(tBu)-Val-Alko-resin (SEQ ID NO: 79) was added 5 mL of a mixed solution of trifluoroacetic acid/water/triisopropylsilane (95/2.5/2.5 (volume ratio)). The mixture was stirred at room temperature for 2.5 hours. The resin was filtered off and the resulting filtrate was added to ice-cold diethyl ether. The resulting precipitate was collected with a glass filter. The residue was washed with diethyl ether and dried in vacuo to give 268 mg of a crude peptide.

3. Purification of Crude Peptide

268 mg of the obtained crude peptide was dissolved in a 20% aqueous acetic acid solution, and purified by reverse phase liquid chromatography.

-   Pump: Shimadzu LC-8A -   Column: YMC-Pack Pro C18 AS12S11-2530WT 3 cmΦ×25 cm -   Eluent 1: H₂O/0.1% TFA -   Eluent 2 (the second eluent): CH₃CN/0.1% TFA -   low rate: 10 mL/min -   Detection: UV220 nm

After equilibrated with the second eluent at a concentration of 1%, the column was loaded with the crude peptide solution. After that, the concentration of the second eluent was allowed to increase to 8% over 30 minutes and subsequently to 14% over 120 minutes. Fractions containing the objective compound were collected, acetonitrile was evaporated off in vacuo and then the residue was freeze-dried. Thus, 105 mg of the objective WT1₁₈₇P2V peptide (SVGEQQYSV; SEQ ID NO: 13; H-Ser-Val-Gly-Glu-Gln-Gln-Tyr-Ser-Val-OH (SEQ ID NO: 13)) was obtained.

The conditions used for HPLC analysis and mass spectrometry of the purified peptide are as follows.

-   HPLC analysis (Shimadzu LC-10Avp) -   Column: YMC-Pack Pro C18 AS-302 4.6 mmΦ×150 mm -   Eluent 1: H₂O/0.1% TFA -   Eluent 2: CH₃CN/0.1% TFA -   Gradient: The concentration of eluent 2 was allowed to increase from     10% to 40% over 30 minutes. -   Flow rate: 1 mL/min -   Detection: UV220 nm -   Purity: 97.4%, Retention time: 11.22 minutes -   Amino acid analysis (Hitachi L-8500 Amino acid analyzer) -   Hydrolysis: 1% phenol/6N aqueous hydrochloric acid solution, 110°     C., 24 hour -   Analysis method: Ninhydrin method -   Ser:1.78(2) Glx:3.26(3)*Gly:(1) Val:2.04(2) Tyr:1.06(1) *)     Gly=standard amino acid, the number in parentheses is a theoretical     value.     Mass Spectrometry (Applied Biosystems API 150EX Mass Spectrometer) -   m/z=996.9 [M+1]⁺ (theoretical value=996.5)     Amino Acid Sequence Analysis (Applied Biosystems 491 Protein     Sequencer)

The amino acid sequence was checked sequentially from the N terminal Ser to the C terminal Val.

The peptides shown in Tables 7 and 8 were synthesized in the same manner as above.

TABLE 7 Amount Amount of of crude purified HPLC Amino SEQ peptide peptide HPLC retention Mass acid ID obtained obtained purity time spectrometry Peptide sequence NO (mg) (mg) (%) (min) (m/z) WT1₁₈₇P2Q SQGEQQYSV 14 251 88 98.2 9.21 1026.0 WT1₁₈₇P2I SIGEQQYSV 15 244 91 97.6 12.98 1010.7 WT1₁₈₇P2M SMGEQQYSV 16 260 22 96.9 11.91 1029.1 WT1₁₈₇P3L SLLEQQYSV 17 238 176 96.8 18.24 1066.9 WT1₁₈₇P3A SLAEQQYSV 18 268 172 99.1 13.67 1024.8 WT1₁₈₇P3V SLVEQQYSV 19 267 182 98.7 15.26 1052.8 WT1₁₈₇P3M SLMEQQYSV 20 280 63 94.8 16.12 1084.8 WT1₁₈₇P3P SLPEQQYSV 21 227 132 98.1 14.02 1050.8 WT1₁₈₇P3W SLWEQQYSV 22 248 40 99.4 20.00 1139.5 (of crude peptide 100 mg) WT1₁₈₇P3F SLFEQQYSV 23 224 110 98.3 19.44 1100.8 WT1₁₈₇P3Y SLYEQQYSV 24 236 114 98.5 15.76 1116.7 WT1₁₈₇P3S SLSEQQYSV 25 261 130 99.1 13.33 1040.8 WT1₁₈₇P3I SLIEQQYSV 26 270 162 97.3 17.51 1066.9

TABLE 8 Amount Amount of of crude purified HPLC Amino SEQ peptide peptide HPLC retention Mass acid ID obtained obtained purity time spectrometry Peptide sequence NO (mg) (mg) (%) (min) (m/z) WT1₁₂₆P2V RVFPNAPYL 36 253 130 96.5 20.65 1077.1 WT1₁₂₆P2Q RQFPNAPYL 37 274 87 98.7 18.43 1106.1 WT1₁₂₆P2A RAFPNAPYL 38 240 63 99.0 19.03 1049.1 WT1₁₂₆P9A RMFPNAPYA 50 262 139 94.3 16.59 1066.8 WT1₁₂₆P9M RMFPNAPYM 52 295 167 95.7 19.75 1126.8

The peptides shown in Tables 9 to 12 were similarly synthesized, but the conditions used for HPLC analysis and mass spectrometry of the purified peptides are as follows. HPLC analysis (Agilent HP1100 or Thermo Fisher Scientific Surveyor)

-   Column: Thermo Fischer Scientific BioBasic-18 3 mmΦ×250 mm -   Eluent 1: H₂O/0.1% TFA -   Eluent 2: CH₃CN/0.1% TFA     Gradient: The concentration of eluent 2 was allowed to change to the     concentration shown in the table over 20 minutes. -   Flow rate: 0.4 mL/min -   Detection: 215 nm     Mass Spectrometry     Thermo Bioanalysis Dynamo Mass Spectrometer (MALDI-TOF)

TABLE 9 HPLC reten- Mass Amino SEQ HPLC tion HPLC spectrom- acid ID purity time gradi- etry Peptide sequence NO (%) (min) ent (m/z) WT1₁₈₇P1G GLGEQQYSV 4 100 12.72  5-60% 980.7 WT1₁₈₇P1A ALGEQQYSV 5 98.9 12.00 10-50% 993.0 WT1₁₈₇P1V VLGEQQYSV 6 98.9 14.98  5-50% 1022.3 WT1₁₈₇P1L LLGEQQYSV 7 97.6 12.75 10-65% 1037.6 WT1₁₈₇P1I ILGEQQYSV 8 98.8 13.46  5-60% 1037.2 WT1₁₈₇P1M MLGEQQYSV 9 95.5 14.15  5-60% 1054.0 WT1₁₈₇P1W WLGEQQYSV 10 98.9 15.60  5-60% 1109.9 WT1₁₈₇P1F FLGEQQYSV 11 95.8 13.14 10-65% 1070.8 WT1₁₈₇P9L SLGEQQYSL 53 95.4 12.49 10-55% 1024.6

TABLE 10 HPLC reten- Mass Amino SEQ HPLC tion HPLC spectrom- acid ID purity time gradi- etry Peptide sequence NO (%) (min) ent (m/z) WT1₁₂₆P1G GMFPNAPYL 27 99.6 15.39 10-70% 1009.5 WT1₁₂₆P1A AMFPNAPYL 28 98.8 13.79 10-85% 1023.3 WT1₁₂₆P1V VMFPNAPYL 29 98.4 14.00 10-85% 1052.2 WT1₁₂₆P1L LMFPNAPYL 30 98.9 14.91 10-80% 1066.3 WT1₁₂₆P1I IMFPNAPYL 31 99.2 13.93 10-80% 1065.4 WT1₁₂₆P1M MMFPNAPYL 32 100 13.77 10-80% 1083.5 WT1₁₂₆P1W WMFPNAPYL 33 97.5 15.64 10-80% 1139.3 WT1₁₂₆P1F FMFPNAPYL 34 98.8 14.78 10-85% 1099.7 WT1₁₂₆P2L RLFPNAPYL 39 98.6 13.11 10-80% 1090.9 WT1₁₂₆P2I RIFPNAPYL 40 100 13.74 10-70% 1090.1 WT1₁₂₆P3I RMIPNAPYL 41 97.4 14.17 10-70% 1076.7 WT1₁₂₆P3L RMLPNAPYL 42 100 13.88 10-65% 1076.4 WT1₁₂₆P3G RMGPNAPYL 43 96.7 12.63 10-65% 1020.9 WT1₁₂₆P3A RMAPNAPYL 44 95.2 13.95 10-60% 1034.9 WT1₁₂₆P3V RMVPNAPYL 45 92.9 14.67 10-60% 1062.7 WT1₁₂₆P3M RMMPNAPYL 46 91.8 14.87 10-60% 1094.8 WT1₁₂₆P3P RMPPNAPYL 47 95.8 13.56 10-65% 1058.8 WT1₁₂₆P3W RMWPNAPYL 48 99.6 15.21 10-70% 1149.7 WT1₁₂₆P9V RMFPNAPYV 49 99.2 13.86 10-60% 1096.5 WT1₁₂₆P9I RMFPNAPYI 51 99.4 14.00 10-65% 1110.7

TABLE 11 HPLC reten- Mass Amino SEQ HPLC tion spec- acid ID purity time HPLC trometry Peptide sequence NO (%) (min) gradient (m/z) WT1₁₈₇P1D DLGEQQYSV 54 96.6 13.43  5-60% 1038.2 WT1₁₈₇P1E ELGEQQYSV 55 96.4 11.83 10-60% 1052.2 WT1₁₈₇P1H HLGEQQYSV 56 98.0 15.79  5-40% 1060.2 WT1₁₈₇P1K KLGEQQYSV 57 99.0 13.77  5-45% 1052.2 WT1₁₈₇P1N NLGEQQYSV 58 95.8 14.34  5-50% 1037.0 WT1₁₈₇P1P PLGEQQYSV 59 95.9 14.68  5-50% 1020.0 WT1₁₈₇P1Q QLGEQQYSV 60 96.8 13.28  5-60% 1051.3 WT1₁₈₇P1R RLGEQQYSV 61 100 13.27  5-60% 1079.6 WT1₁₈₇P1T TLGEQQYSV 62 96.7 14.40  5-50% 1025.0

TABLE 12 HPLC reten- Mass Amino SEQ HPLC tion spec- acid ID purity time HPLC trometry Peptide sequence NO (%) (min) gradient (m/z) WT1₁₂₆P1D DMFPNAPYL 63 99.2 14.72 10-75% 1067.3 WT1₁₂₆P1E EMFPNAPYL 64 99.1 15.20  5-70% 1082.1 WT1₁₂₆P1H HMFPNAPYL 65 96.7 14.52 10-70% 1089.9 WT1₁₂₆P1K KMFPNAPYL 66 95.9 13.96 10-75% 1080.0 WT1₁₂₆P1N NMFPNAPYL 67 99.8 14.69 10-75% 1066.3 WT1₁₂₆P1P PMFPNAPYL 68 96.9 14.26 10-80% 1049.3 WT1₁₂₆P1Q QMFPNAPYL 69 95.1 14.94 10-70% 1080.3 WT1₁₂₆P1S SMFPNAPYL 70 99.8 14.28 10-80% 1040.8 WT1₁₂₆P1T TMFPNAPYL 71 98.8 13.72 10-85% 1053.5 WT1₁₂₆ RIFPNAPYI 72 97.0 14.23 10-65% 1089.5 P2I&P9I WT1₁₂₆ RIFPNAPYV 73 100 12.23 10-80% 1077.0 P2I&P9V WT1₁₂₆ RLFPNAPYI 74 97.7 13.43 10-75% 1090.8 P2L&P9I WT1₁₂₆ RLFPNAPYV 75 97.0 12.83 10-75% 1076.9 P2L&P9V

Example 14 Evaluation of Modified Peptides on the Activity of Inducing Specific Immune Cells Using HLA-A*0201-expressing Transgenic Mice, and Confirmation of Cross Reactivity of Induced Specific Immune Cells to the Wild-type Peptide

<Methods>

(1) Modified Peptide Candidates

As for the WT1₁₈₇ peptide, the WT1₁₂₆ peptide, and modified peptides thereof (peptides comprising substitution of one or two amino acid residues at position 1, 2, 3 and/or 9 from the N terminus of the WT1₁₈₇ peptide or the WT1₁₂₆ peptide), the affinity against HLA-A*0201 molecules was analyzed using the known method in the technical field, i.e., the method mediated by the following four computer databases: BIMAS (http://www.mpiib-berlin.mpg.de/MAPPP/binding.html), SYFPEITHI http://www.mpiib-berlin.mpg.de/MAPPP/binding.html), RANLPEP (http://immunax.dfci.harvard.edu/Tools/rankpep.html), and NetMHC3.0 (http://www.cbs.dtu.dk/services/NetMHC/). The analysis results of the WT1₁₈₇ peptide and its modified peptides are shown in Tables 13 to 16 and 21. The analysis results of the WT1₁₂₆ peptide and its modified peptides are shown in Tables 17 to 20 and 22 to 23. The predicted affinity is shown in scores.

TABLE 13 Amino SEQ Pep- acid ID HLA-A*0201 binding score tide sequence NO BIMAS SYFPEITHI RANKPEP NetMHC3.0 WT1₁₈₇ SLGEQQYSV 2 285 27 96/ 0.721 64.43% WT1₁₈₇ ALGEQQYSV 5 285 27 95/ 0.720 P1A 63.76% WT1₁₈₇ FLGEQQYSV 11 1312 26 82/ 0.862 P1F 55.03% WT1₁₈₇ GLGEQQYSV 4 285 26 86/ 0.672 P1G 57.72% WT1₁₈₇ ILGEQQYSV 8 485 27 90/ 0.698 P1I 60.40% WT1₁₈₇ LLGEQQYSV 7 485 27 89/ 0.719 P1L 59.73% WT1₁₈₇ MLGEQQYSV 9 485 25 92/ 0.770 P1M 61.74% WT1₁₈₇ VLGEQQYSV 6 485 26 92/ 0.705 P1V 61.74% WT1₁₈₇ WLGEQQYSV 10 1312 25 71/ 0.693 P1W 47.65%

TABLE 14 Amino SEQ Pep- acid ID HLA-A*0201 binding score tide sequence NO BIMAS SYFPEITHI RANKPEP NetMHC3.0 WT1₁₈₇ SLGEQQYSV 2 285 27 96/ 0.721 64.43% WT1₁₈₇ SIGEQQYSV 15 39 25 85/ 0.556 P2I 57.05% WT1₁₈₇ SMGEQQYSV 16 206 25 84/ 0.740 P2M 56.38% WT1₁₈₇ SQGEQQYSV 14 29 17 52/ 0.455 P2Q 34.90% WT1₁₈₇ SVGEQQYSV 13 25 21 78/ 0.461 P2V 52.35%

TABLE 15 Amino SEQ acid ID HLA-A*0201 binding score Peptide sequence NO BIMAS SYFPEITHI RANKPEP NetMHC3.0 WT1₁₈₇ SLGEQQYSV 2 285 27  96/64.43% 0.721 WT1₁₈₇P3A SLAEQQYSV 18 285 29 110/73.83% 0.811 WT1₁₈₇P3F SLFEQQYSV 23 1055 28 114/76.51% 0.852 WT1₁₈₇P3I SLIEQQYSV 26 285 29 115/77.18% 0.817 WT1₁₈₇P3L SLLEQQYSV 17 1055 29 116/77.85% 0.839 WT1₁₈₇P3M SLMEQQYSV 20 1055 28 114/76.51% 0.876 WT1₁₈₇P3P SLPEQQYSV 21 285 27  95/63.76% 0.748 WT1₁₈₇P3S SLSEQQYSV 25 285 27 110/73.83% 0.793 WT1₁₈₇P3V SLVEQQYSV 19 285 27 113/75.84% 0.766 WT1₁₈₇P3W SLWEQQYSV 22 2367 28  98/65.77% 0.863 WT1₁₈₇P3Y SLYEQQYSV 24 913 28 111/74.50% 0.854

TABLE 16 Amino SEQ Pep- acid ID HLA-A*0201 binding score tide sequence NO BIMAS SYFPEITHI RANKPEP NetMHC3.0 WT1₁₈₇ SLGEQQYSV 2 285 27 96/ 0.721 64.43% WT1₁₈₇ SLGEQQYSL 53 88 27 89/ 0.640 P9L 59.73%

TABLE 17 Amino SEQ Pep- acid ID HLA-A*0201 binding score tide sequence NO BIMAS SYFPEITHI RANKPEP NetMHC3.0 WT1₁₂₆ RMFPNAPYL 3 314 22 70/ 0.802 46.98% WT1₁₂₆ AMFPNAPYL 28 314 24 77/ 0.808 P1A 51.68% WT1₁₂₆ FMFPNAPYL 34 1444 23 64/ 0.909 P1F 42.95% WT1₁₂₆ GMFPNAPYL 27 314 23 68/ 0.795 P1G 45.64% WT1₁₂₆ IMFPNAPYL 31 534 24 72/ 0.802 P1I 48.32% WT1₁₂₆ LMFPNAPYL 30 534 24 71/ 0.819 P1L 47.65% WT1₁₂₆ MMFPNAPYL 32 534 22 74/ 0.852 P1M 49.66% WT1₁₂₆ VMFPNAPYL 29 534 23 74/ 0.804 P1V 49.66% WT1₁₂₆ WMFPNAPYL 33 1444 22 53/ 0.799 P1W 35.57%

TABLE 18 Amino SEQ Pep- acid ID HLA-A*0201 binding score tide sequence NO BIMAS SYFPEITHI RANKPEP NetMHC3.0 WT1₁₂₆ RMFPNAPYL 3 314 22 70/ 0.802 46.98% WT1₁₂₆ RAFPNAPYL 38 6 18 47/ 0.376 P2A 31.54% WT1₁₂₆ RIFPNAPYL 40 60 22 71/ 0.640 P2I 47.65% WT1₁₂₆ RLFPNAPYL 39 435 24 82/ 0.784 P2L 55.03% WT1₁₂₆ RQFPNAPYL 37 44 14 38/ 0.485 P2Q 25.50% WT1₁₂₆ RVFPNAPYL 36 38 18 64/ 0.552 P2V 42.95%

TABLE 19 Amino SEQ Pep- acid ID HLA-A*0201 binding score tide sequence NO BIMAS SYFPEITHI RANKPEP NetMHC3.0 WT1₁₂₆ RMFPNAPYL 3 314 22 70/ 0.802 46.98% WT1₁₂₆ RMAPNAPYL 44 85 23 66/ 0.734 P3A 44.30% WT1₁₂₆ RMGPNAPYL 43 85 21 52/ 0.602 P3G 34.90% WT1₁₂₆ RMIPNAPYL 41 85 23 71/ 0.741 P3I 47.65% WT1₁₂₆ RMLPNAPYL 42 314 23 72/ 0.781 P3L 48.32% WT1₁₂₆ RMMPNAPYL 46 314 22 70/ 0.834 P3M 46.98% WT1₁₂₆ RMPPNAPYL 47 85 21 51/ 0.613 P3P 34.23% WT1₁₂₆ RMVPNAPYL 45 85 21 69/ 0.680 P3V 46.31% WT1₁₂₆ RMWPNAPYL 48 2293 22 61/ 0.867 P3W 40.94%

TABLE 20 Amino SEQ Pep- acid ID HLA-A*0201 binding score tide sequence NO BIMAS SYFPEITHI RANKPEP NetMHC3.0 WT1₁₂₆ RMFPNAPYL 3 314 22 70/ 0.802 46.98% WT1₁₂₆ RMFPNAPYA 50 73 16 53/ 0.731 P9A 35.57% WT1₁₂₆ RMFPNAPYI 51 153 20 74/ 0.790 P9I 49.66% WT1₁₂₆ RMFPNAPYM 52 73 16 65/ 0.686 P9M 43.62% WT1₁₂₆ RMFPNAPYV 49 1022 22 77/ 0.838 P9V 51.68%

TABLE 21 Amino SEQ Pep- acid ID HLA-A*0201 binding score tide sequence NO BIMAS SYFPEITHI RANKPEP NetMHC3.0 WT1₁₈₇ SLGEQQYSV 2 285 27 96/ 0.721 64.43% WT1₁₈₇ DLGEQQYSV 54 21 24 81/ 0.252 P1D 54.36% WT1₁₈₇ ELGEQQYSV 55 21 22 85/ 0.366 P1E 57.05% WT1₁₈₇ HLGEQQYSV 56 10 25 83/ 0.610 P1H 55.70% WT1₁₈₇ KLGEQQYSV 57 998 26 89/ 0.745 P1K 59.73% WT1₁₈₇ NLGEQQYSV 58 285 25 90/ 0.613 P1N 60.40% WT1₁₈₇ PLGEQQYSV 59 6 22 78/ 0.287 P1P 52.35% WT1₁₈₇ QLGEQQYSV 60 285 25 87/ 0.630 P1Q 58.39% WT1₁₈₇ RLGEQQYSV 61 285 25 88/ 0.690 P1R 59.06% WT1₁₈₇ TLGEQQYSV 62 285 25 93/ 0.669 P1T 62.42%

TABLE 22 Amino SEQ Pep- acid ID HLA-A*0201 binding score tide sequence NO BIMAS SYFPEITHI RANKPEP NetMHC3.0 WT1₁₂₆ RMFPNAPYL 3 314 22 70/ 0.802 46.98% WT1₁₂₆ DMFPNAPYL 63 24 21 63/ 0.353 P1D 42.28% WT1₁₂₆ EMFPNAPYL 64 24 19 67/ 0.501 P1E 44.97% WT1₁₂₆ HMFPNAPYL 65 11 22 65/ 0.747 P1H 43.62% WT1₁₂₆ KMFPNAPYL 66 1099 23 71/ 0.841 P1K 47.65% WT1₁₂₆ NMFPNAPYL 67 314 22 72/ 0.734 P1N 48.32% WT1₁₂₆ PMFPNAPYL 68 7 19 60/ 0.802 P1P 40.27% WT1₁₂₆ QMFPNAPYL 69 314 22 69/ 0.757 P1Q 46.31% WT1₁₂₆ SMFPNAPYL 70 314 24 78/ 0.819 P1S 52.35% WT1₁₂₆ TMFPNAPYL 71 314 22 75/ 0.779 P1T 50.34%

TABLE 23 Amino SEQ Pep- acid ID HLA-A*0201 binding score tide sequence NO BIMAS SYFPEITHI RANKPEP NetMHC3.0 WT1₁₂₆ RMFPNAPYL 3 314 22 70/ 0.802 46.98% WT1₁₂₆ RIFPNAPYI 72 29 20 75/ 0.617 P2I& 50.34% P9I WT1₁₂₆ RIFPNAPYV 73 195 22 78/ 0.722 P2I& 52.35% P9V WT1₁₂₆ RLFPNAPYI 74 212 22 86/ 0.780 P2L& 57.72% P9I WT1₁₂₆ RLFPNAPYV 75 1415 24 89/ 0.818 P2L& 59.73% P9V

A modified peptide which was predicted to have an equal or higher affinity compared with the wild-type peptide (the WT1₁₈₇ peptide or the WT1₁₂₆ peptide) in at least one of the databases was selected as a sample to be tested in the following (2) to (4), in addition to wild-type peptides.

(2) Preparation and Administration of Peptide Preparations

A peptide synthesized and freeze-dried in Example 13 was prepared at the concentration of 40 mg/mL in DMSO (manufactured by Nacalai Tesque, Inc.). After that, 32.5 μL of the prepared DMSO solution of the peptide was mixed with 540 μL of distilled water for injection (manufactured by Otsuka Pharmaceutical Factory, Inc.). Next, 550 μL of the mixture was mixed with 700 μL of the Freund's incomplete adjuvant (Montanide ISA-51) using a glass syringe to prepare a water-in-oil emulsion. An HLA-A*0201-expressing transgenic mouse (strain name: HLA-A2+HLA-DR1+/Iaβ° β2m, EMMA ID number EM: 01783) was immunized by subcutaneous administration of 300 μL of the preparation (water-in-oil emulsion) into the base of the tail. The evaluation of each peptide was performed using 2 or 3 mice.

(3) Preparation of Splenic Cells

The spleen was isolated 7 days after immunization. The spleen was smashed by rubbing against the frothed part of a slide glass and then subjected to hemolysis treatment with ACK Lysing Buffer (manufactured by Lonza Co.) to prepare splenic cells. In this experiment, CTM (Complete T-cell Medium: RPMI-1640 medium (manufactured by Invitrogen Corporation) supplemented by 10% FBS, 10 mM HEPES, 20 mM L-glutamine, 1 mM sodium pyruvate, 1 mM MEM non-essential amino acid, 1% MEM vitamin and 55 μM 2-mercaptoethanol with the proviso that these concentrations were all final concentrations) was used as the medium for the splenic cells, and the cell suspension was prepared at the concentration of 5×10⁶ cells/mL.

(4) Elispot Method

Whether the administered peptide has the activity of inducing WT1-specific immune cells was examined by the ELISPOT method using IFNγ as an index. The method was performed according to the attached manual. After the CTM was added in a volume of 50 μL/well into plates for ELISPOT (manufactured by BD Japan, catalog No. 551083), the splenic cell suspension was plated therein in a volume of 100 μL (5×10⁵ cells/well). Further, the administered peptide or the wild-type peptide was added thereto in a volume of 50 μL/well (peptide final concentration: 2 μg/mL). This assay method is known as one of the substitute methods that enable prediction of cytotoxic activity (J. Immunological Methods, 1995, 181, 45-54).

<Results>

The evaluation results of the activity of inducing specific cell-mediated immunity are shown in FIGS. 19 to 22 and 28 to 29 for the modified WT1₁₈₇ peptides, and in FIGS. 23 to 27 and 30 to 32 for the modified WT1₁₂₆ peptides. In each of FIGS. 19 to 32, the vertical axis represents the number of antigen peptide-specific responsive cells in 5×10⁵ splenic cells (spots/5×10⁵ cells), and the horizontal axis represents the individual mouse (2 or 3 mice) used for evaluation. The white bar represents the number of the specific immune cells responded under no stimulation with antigen peptides. The gray bar represents the number of the specific immune cells responded to stimulation with the wild-type peptide. The black bar represents the number of the specific immune cells responded to stimulation with the administered (modified) peptide.

FIGS. 19 to 32 show the respective activities of inducing specific cell-mediated immunity regarding the following peptides.

FIG. 19 a: WT1₁₈₇P1A peptide, b: WT1₁₈₇P1F peptide, c: WT1₁₈₇P1G peptide, d: WT1₁₈₇P1I peptide, e: WT1₁₈₇P1L peptide, f: WT1₁₈₇P1M peptide.

FIG. 20 a: WT1₁₈₇P1V peptide, b: WT1₁₈₇P1W peptide, c: WT1₁₈₇P2I peptide, d: WT1₁₈₇P2M peptide, e: WT1₁₈₇P2Q peptide, f: WT1₁₈₇P2V peptide.

FIG. 21 a: WT1₁₈₇P3A peptide, b: WT1₁₈₇P3F peptide, c: WT1₁₈₇P3I peptide, d: WT1₁₈₇P3L peptide, e: WT1₁₈₇P3M peptide, f: WT1₁₈₇ P3P peptide.

FIG. 22 a: WT1₁₈₇P3S peptide, b: WT1₁₈₇P3V peptide, c: WT1₁₈₇P3W peptide, d: WT1₁₈₇P3Y peptide, e: WT1₁₈₇P9L peptide.

FIG. 23 a: WT1₁₂₆P1A peptide, b: WT1₁₂₆P1F peptide, c: WT1₁₂₆P1G peptide, d: WT1₁₂₆P1I peptide, e: WT1₁₂₆P1L peptide, f: WT1₁₂₆P1M peptide.

FIG. 24 a: WT1₁₂₆P1V peptide, b: WT1₁₂₆P1W peptide, c: WT1₁₂₆P2A peptide, d: WT1₁₂₆P2I peptide, e: WT1₁₂₆P2L peptide, f: WT1₁₂₆P2Q peptide.

FIG. 25 a: WT1₁₂₆P2V peptide, b: WT1₁₂₆P3A peptide, c: WT1₁₂₆P3G peptide, d: WT1₁₂₆P3I peptide, e: WT1₁₂₆P3L peptide, f: WT1₁₂₆P3M peptide.

FIG. 26 a: WT1₁₂₆P3P peptide, b: WT1₁₂₆P3V peptide, c: WT1₁₂₆P3W peptide, d: WT1₁₂₆P9A peptide, e: WT1₁₂₆P9I peptide, fWT1₁₂₆P9M peptide.

FIG. 27: WT1₁₂₆P9V peptide.

FIG. 28 a: WT1₁₈₇P1D peptide, b: WT1₁₈₇P1E peptide, c: WT1₁₈₇P1H peptide, d: WT1₁₈₇P1K peptide.

FIG. 29 a: WT1₁₈₇P1N peptide, b: WT1₁₈₇P1P peptide, c: WT1₁₈₇P1Q peptide, d: WT1₁₈₇P1R peptide, e: WT1₁₈₇P1T peptide.

FIG. 30 a: WT1₁₂₆P1D peptide, b: WT1₁₂₆P1E peptide, c: WT1₁₂₆P1H peptide, d: WT1₁₂₆P1K peptide, e: WT1₁₂₆P1N peptide, f: WT1₁₂₆P1P peptide.

FIG. 31 a: WT1₁₂₆P1Q peptide, b: WT1₁₂₆P1S peptide, c: WT1₁₂₆P1T peptide, d: WT1₁₂₆P2I&P91 peptide, e: WT1₁₂₆P2I&P9V peptide, f: WT1₁₂₆P2L&P9I peptide.

FIG. 32: WT1₁₂₆P2L&P9V peptide.

As shown in these results, when the modified peptides except the WT1₁₈₇P1D peptide, the WT1₁₈₇P1E peptide, the WT1₁₈₇P1H peptide, the WT1₁₈₇P1P peptide and the WT1₁₈₇P2Q peptide; the WT1₁₂₆P1D peptide, the WT1₁₂₆P1E peptide, the WT1₁₂₆P1P peptide, the WT1₁₂₆P2A peptide and the WT1₁₂₆P2Q peptide were administered into the mice, specific immune cells were remarkably induced in an efficient manner.

Next, the specific immune cells induced by stimulation of the modified peptide were analyzed for the cross reactivity to the wild-type peptide (Tables 24 to 25). The results show that particularly the WT1₁₈₇P1A peptide, the WT1₁₈₇P1I peptide, the WT1₁₈₇P1L peptide, the WT1₁₈₇P1M peptide, the WT1₁₈₇P1N peptide, the WT1₁₈₇P1Q peptide, the WT1₁₈₇P1T peptide, the WT1₁₈₇P1V peptide, the WT1₁₈₇P2V peptide, the WT1₁₈₇P2M peptide, the WT1₁₈₇P2I peptide, the WT1₁₈₇P3A peptide, the WT1₁₈₇P3F peptide, the WT1₁₈₇ P3P peptide, the WT1₁₈₇P3S peptide, the WT1₁₈₇P3V peptide and the WT1₁₈₇P9L peptide among the WT1₁₈₇ modified peptides; and the WT1₁₂₆P1S peptide, the WT1₁₂₆P2I peptide, the WT1₁₂₆P2L peptide, the WT1₁₂₆P2V peptide, the WT1₁₂₆P3W peptide, the WT1₁₂₆P9I peptide, the WT1₁₂₆P9M peptide and the WT1₁₂₆P9V peptide among the WT1₁₂₆ modified peptides, can induce specific immune cells that can efficiently recognize both of the modified peptide and the wild-type peptide.

TABLE 24 Cross Modified WT1₁₈₇ peptide reactivity modified at modified at modified at modified at (%) position 1 position 2 position 3 position 9 80-100 WT1₁₈₇P1A WT1₁₈₇P2V WT1₁₈₇P3A WT1₁₈₇P9L WT1₁₈₇P1N WT1₁₈₇P2M WT1₁₈₇P3P WT1₁₈₇P1Q WT1₁₈₇P2I WT1₁₈₇P3S WT1₁₈₇P1T WT1₁₈₇P1V 60-80 WT1₁₈₇P1I WT1₁₈₇P3F WT1₁₈₇P1L WT1₁₈₇P3V WT1₁₈₇P1M 40-60 WT1₁₈₇P1R WT1₁₈₇P3Y 20-40 WT1₁₈₇P1F WT1₁₈₇P3L WT1₁₈₇P1W  0-20 WT1₁₈₇P1G WT1₁₈₇P3I WT1₁₈₇P1K WT1₁₈₇P3M WT1₁₈₇P3W ND* WT1₁₈₇P1D WT1₁₈₇P2Q WT1₁₈₇P1E WT1₁₈₇P1H WT1₁₈₇P1P

TABLE 25 Modified WT1₁₂₆ peptide Cross modified modified modified modified modified at reactivity at at at at positions (%) position 1 position 2 position 3 position 9 2&9 80-100 WT1₁₂₆P2L WT1₁₂₆P3W WT1₁₂₆P9M WT1₁₂₆P2V WT1₁₂₆P9I 60-80 WT1₁₂₆P1S WT1₁₂₆P2I WT1₁₂₆P9V 40-60 WT1₁₂₆P1A WT1₁₂₆P1H WT1₁₂₆P1K WT1₁₂₆P1M WT1₁₂₆P1N 20-40 WT1₁₂₆P1G WT1₁₂₆P9A WT1₁₂₆P1I WT1₁₂₆P1Q WT1₁₂₆P1W  0-20 WT1₁₂₆P1F WT1₁₂₆P3A WT1₁₂₆P2I&P9I WT1₁₂₆P1L WT1₁₂₆P3G WT1₁₂₆P2I&P9V WT1₁₂₆P1T WT1₁₂₆P3I WT1₁₂₆P2L&P9I WT1₁₂₆P1V WT1₁₂₆P3L WT1₁₂₆P2L&P9V WT1₁₂₆P3M WT1₁₂₆P3P WT1₁₂₆P3V ND* WT1₁₂₆P1D WT1₁₂₆P2Q WT1₁₂₆P1E WT1₁₂₆P2A WT1₁₂₆P1P ND*: unmeasurable due to no activity shown

INDUSTRIAL APPLICABILITY

The cancer vaccine composition of the present invention is useful as a medicament used for treatment and prevention of WT1-expressing cancers in HLA-A*0206-positive persons. The cancer vaccine composition of the present invention is also useful as a medicament used for treatment and prevention of WT1-expressing cancers in HLA-A*0201-positive persons. 

The invention claimed is:
 1. A method of cancer treatment, comprising administering to an HLA-A*0201-positive person a composition comprising the following peptide: a modified peptide of the WT1₁₈₇ peptide: Ser Leu Gly Glu Gln Gln Tyr Ser Val (SEQ ID NO: 2) or the WT1₁₂₆ peptide: Arg Met Phe Pro Asn Ala Pro Tyr Leu (SEQ ID NO: 3), wherein the modified peptide is a peptide comprising the amino acid residues at position 4 to 8 from the N terminus of the WT1₁₈₇ or WT1₁₂₆ peptide and is immunogenic in HLA-A*0201-positive persons.
 2. The method of claim 1, wherein the peptide is a modified peptide of WT1₁₈₇ peptide.
 3. The method of claim 1, wherein the peptide is a modified peptide of WT1₁₂₆ peptide.
 4. The method of claim 1, wherein the peptide is SEQ ID NO: 11, 16, 20, 34, 39, 46 or
 49. 5. A method of cancer treatment, comprising administering an HLA-A*0201-positive person a composition comprising: a modified peptide of the WT1₁₈₇ peptide: Ser Leu Gly Glu Gln Gln Tyr Ser Val (SEQ ID NO: 2) or the WT1₁₂₆ peptide: Arg Met Phe Pro Asn Ala Pro Tyr Leu (SEQ ID NO: 3), either of which is a partial peptide of a protein which is a gene product of the tumor suppressor gene WT1, the modified peptide being immunogenic in HLA-A*0201-positive persons. 